View source for Salar de Uyuni

{{AI-generated|date=November 2025}}
{{Use dmy dates|date=June 2021}}
{{Short description|Salt flat in Bolivia}}
{{Infobox landform
| water = 
| name = Salar de Uyuni
| photo = Salar Uyuni au01.jpg
| photo_caption = Hexagonal formations in the Salar de Uyuni during the dry season.
| elevation_m = 3663
| elevation_ref = 
| area = {{Convert|10582|km2|sqmi}}
| depth = {{Convert|130|m|ft}}
| formed_by = [[Evaporation]]
| map = Bolivia
| map_relief = 1 
| map_caption = Location within Bolivia
| label_position = none
| location = [[Daniel Campos Province]], [[Potosí Department|Potosí]], Bolivia
| coordinates = {{coord|20|08|01.59|S|67|29|20.88|W|scale:30000|display=inline,title}}
| topo = 
| type = [[Dry lake]]
| age = 
| volcanic_arc/belt = 
| last_eruption = 
|length=average of {{convert|126|km|mi|abbr=on}}|other_name={{native name|es|Salar de Tunupa}}|width=average of {{convert|84|km|mi|abbr=on}}|subdivision_name=|geology=[[Salt pan (geology)|Salt pan]]}}

'''Salar de Uyuni''' (also referred to as "Salar de Tunupa")<ref>{{cite web|title=Salar de Tunupa|url=http://www.irisentoreopreis.nl/tunupa_map.shtml|website=Iris en Tore op reis|access-date=26 February 2016|date=29 July 2011|archive-date=19 January 2016|archive-url=https://web.archive.org/web/20160119054358/http://www.irisentoreopreis.nl/tunupa_map.shtml|url-status=dead}}</ref> is the largest [[Salt pan (geology)|salt flat]] ([[Dry lake|dry lake bed]]) in the world, with an area of approximately of {{convert|10,582|km2|mi2}}.<ref name="NASA2019">{{cite web |title=Lithium Harvesting at Salar de Uyuni |url=https://earthobservatory.nasa.gov/images/144976/lithium-harvesting-at-salar-de-uyuni |website=Earth Observatory | publisher=[[NASA]] |language=en |date=April 12, 2013}}</ref><ref>{{Cite book |last=Mills |first=Andrea |title=Strange but True |publisher=Penguin Random House |isbn=978-3-8310-3074-3 |edition=1st |location=London |publication-date=2015 |pages=8–9}}</ref> It is situated in southwestern [[Bolivia]], within the [[Daniel Campos Province]] of the [[Potosí Department]], near the crest of the [[Andes|Andes Mountains]], at an elevation of {{convert|3,656|m|ft|abbr=on}} above sea level.<ref name=britannica>{{Cite encyclopedia |title=Uyuni Salt Flat |encyclopedia=[[Encyclopædia Britannica]] |url=http://www.britannica.com/eb/article-90745/88?query=Salar%20de%20Uyuni&ct= |access-date=1 December 2007}}{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The Salar was formed as a result of transformations between several prehistoric lakes that existed around forty thousand years ago but had all evaporated over time.{{r|NASA2019}} It is now covered by a few meters of salt crust, which has an extraordinary flatness with the average elevation variations within one meter over the entire area of the Salar. The crust serves as a source of salt and covers a pool of [[brine]], which is exceptionally rich in [[lithium]]. The large area, clear skies, and exceptional flatness of the surface make the Salar ideal for calibrating the [[altimeter]]s of Earth observation satellites.<ref name="nature2">{{cite journal |last1=Hand |first1=Eric |title=The salt flat with curious curves |journal=Nature |date=30 November 2007 |doi=10.1038/news.2007.315 }}</ref><ref name="geo">{{cite journal |last=Fricker |first=H. A. |year=2005 |title=Assessment of ICESat performance at the salar de Uyuni, Bolivia |journal=[[Geophysical Research Letters]] |volume=32 |issue=21 |page=L21S06 |article-number=2005GL023423 |bibcode=2005GeoRL..3221S06F |doi=10.1029/2005GL023423 }}</ref><ref name="refl">{{cite journal |last1=Reuder |first1=Joachim |last2=Ghezzi |first2=F. |last3=Palenque |first3=E. |last4=Torrez |first4=R. |last5=Andrade |first5=M. |last6=Zaratti |first6=F. |display-authors=1 |year=2007 |title=Investigations on the effect of high surface albedo on erythemally effective UV irradiance: Results of a campaign at the Salar de Uyuni, Bolivia |journal=Journal of Photochemistry and Photobiology |volume=87 |issue=1 |pages=1–8 |bibcode=2007JPPB...87....1R |doi=10.1016/j.jphotobiol.2006.12.002 |pmid=17227712 }}</ref><ref>{{cite news |bibcode=2002AGUFMOS52A0193B |title=GPS Survey of the salar de Uyuni, Bolivia, for Satellite Altimeter Calibration |last=Borsa |first=A. A |publisher=American Geophysical Union, Fall Meeting |year=2002 |display-authors=etal}}</ref><ref name=ieee>{{cite journal
|last1=Lamparelli |first1=R. A. C. |title=Characterization of the Salar de Uyuni for in-orbit satellite calibration |journal=[[IEEE Geoscience and Remote Sensing Society|IEEE Trans. Geosci. Remote Sens.]] |volume=41 |issue=6 |pages=1461–1468 |year=2003 |doi=10.1109/TGRS.2003.810713 |display-authors=1 |last2=Ponzoni |first2=F. J. |last3=Zullo |first3=J. |last4=Queiroz Pellegrino |first4=G. |last5=Arnaud |first5=Y. |bibcode=2003ITGRS..41.1461C }}</ref> Following rain, a thin layer of dead calm water transforms the flat into the world's largest mirror, {{convert|129|km|mile|abbr=on}} across.<ref>{{cite news |url=https://www.pbs.org/show/kingdoms-sky/ |title=Kingdoms of the Sky: Salt Flat Landscape Creates the World's Largest Mirror |newspaper=[[PBS]] |date=25 July 2018 |quote=Sudden rains leave a layer of dead calm water just an inch deep, turning the salt flat into a natural wonder: the world's largest mirror, eighty miles across. At night, the landscape is transformed again into a 360-degree starscape. This dazzling show is only possible because the Salar de Uyuni is perfectly flat.}}</ref>

The Salar serves as the major transport route across the Bolivian [[Altiplano]] and is a prime breeding ground for several species of [[flamingo]]s. Salar de Uyuni is also a climatological transitional zone since the towering tropical [[Cumulus congestus cloud|cumulus congestus]] and [[cumulonimbus incus]] clouds that form in the eastern part of the salt flat during the summer cannot permeate beyond its drier western edges, near the Chilean border and the [[Atacama Desert]].{{citation needed|date=June 2016}}

The Salar has been used as a filming location for movies such as ''[[The Fall (2006 film)|The Fall]]'' (2006), ''[[Salt and Fire]]'' (2016), ''The Unseen'' (2017), ''[[Star Wars: The Last Jedi]]'' (2017),<ref>{{cite web |title=Crait: The Salar de Uyuni Star Wars Planet |url=https://www.salardeuyuni.com/salar-de-uyuni-star-wars/ |website=salardeuyuni |date=24 August 2018 |publisher=salardeuyuni.com |access-date=11 April 2020}}</ref><ref>{{cite web |last1=Butler |first1=Alex |title=Star Wars: The Last Jedi filming locations around the world |url=https://www.lonelyplanet.com/articles/star-wars-the-last-jedi-filming-locations |website=Lonely Planet |access-date=11 April 2020}}</ref> and several others.

==Name==
''Salar'' means [[Salt pan (geology)|salt flat]] in Spanish. ''Uyuni'' originates from the [[Aymara language]] and means a [[pen (enclosure)]]; Uyuni is a surname and the name of a town that serves as a gateway for tourists visiting the Salar. Thus ''Salar de Uyuni'' can be loosely translated as a salt flat with enclosures, the latter possibly referring to the "islands" of the Salar; or as "salt-flat at Uyuni (the town named 'pen for animals')".{{citation needed|date=June 2016}}

Aymara legend tells that the mountains [[Tunupa]], Kusku, and Kusina, which surround the Salar, were giant people. Tunupa married Kusku, but Kusku ran away from her with Kusina. Grieving Tunupa started to cry while breastfeeding her son. Her tears mixed with milk and formed the Salar. Many locals consider the Tunupa an important [[deity]] and say that the place should be called Salar de Tunupa rather than Salar de Uyuni.<ref name="trav12">{{cite book |last=Atkinson |first=David |url=https://books.google.com/books?id=WDBYHYwdhuAC&pg=PA174 |title=Bolivia: The Bradt Travel Guide |date=1 March 2007 |publisher=Bradt Travel Guides |isbn=978-1-84162-165-4 |pages=170; 174–176}}</ref>

==Formation, geology, and climate==
[[File:Salar_de_Uyuni-5_(53641294827).jpg|left|thumb|Natural reflections in the Salar de Uyuni during the rainy season]]
The Salar de Uyuni is part of the [[Altiplano]] of Bolivia in South America. The Altiplano is a high plateau, which was formed during uplift of the Andes mountains. The plateau includes fresh and saltwater lakes as well as salt flats and is [[endorheic]].<ref name="nasa">{{cite web |url=http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17120 |archive-url=https://web.archive.org/web/20061001054555/http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17120 |url-status=dead |archive-date=1 October 2006 |title=Salar de Uyuni, Bolivia |publisher=[[NASA Earth Observatory]] |access-date=1 December 2007}}</ref>

The geological history of the Salar is associated with a sequential transformation between several vast lakes. Some 30,000 to 42,000 years ago, the area was part of a giant prehistoric lake, [[Lake Tauca|Lake Minchin]]. Its age was estimated by [[radiocarbon dating]] shells from outcropping [[sediment]]s and [[Carbonate platform|carbonate reefs]] and varies between reported studies. Lake Minchin (named after Juan B. Minchin of Oruro)<ref>{{cite journal |last1=Bowman |first1=Isaiah |title=Results of an Expedition to the Central Andes |journal=Bulletin of the American Geographical Society |date=1914 |volume=46 |issue=3 |pages=161–183 |id={{ProQuest|125750245}} |doi=10.2307/201641 |jstor=201641 }}</ref> later transformed into [[Lake Tauca|Paleo Lake Tauca]] having a maximal depth of {{convert|140|m|sp=us}}, and an estimated age of 13,000 to 18,000 or 14,900 to 26,100 years, depending on the source. The youngest prehistoric lake was Coipasa, which was radiocarbon dated to 11,500 to 13,400 years ago. When it dried, it left behind two modern lakes, [[Lake Poopó|Poopó]] and [[Lago Uru Uru|Uru Uru]], and two major salt deserts, [[Lago Coipasa|Salar de Coipasa]] and the larger Salar de Uyuni. Salar de Uyuni spreads over 10,582&nbsp;km<sup>2</sup>, which is roughly 100 times the size of the [[Bonneville Salt Flats]] in the United States. Lake Poopó is a neighbor of the much larger [[Lake Titicaca]]. During the wet season, Titicaca overflows and discharges into Poopó, which in turn, floods Salar De Coipasa and Salar de Uyuni.<ref name="nature">{{cite journal |journal=[[Nature (journal)|Nature]] |title=Tropical climate changes at millennial and orbital timescales on the Bolivian Altiplano |first1=P. A. |last1=Baker |volume=409 |year=2001 |pmid=11217855 |display-authors=1 |last2=Rigsby |first2=C. A. |last3=Seltzer |first3=G. O. |last4=Fritz |first4=S. C. |last5=Lowenstein |first5=T. K. |last6=Bacher |first6=N. P. |last7=Veliz |first7=C. |issue=6821 |pages=698–701 |doi=10.1038/35055524 |bibcode=2001Natur.409..698B }}</ref>

Lacustrine mud that is interbedded with salt and saturated with brine underlies the surface of Salar de Uyuni. The brine is a saturated solution of [[sodium chloride]], [[lithium chloride]], and [[magnesium chloride]] in water. It is covered with a solid salt crust varying in thickness between tens of centimeters and a few meters. The center of the Salar contains a few islands, which are the remains of the tops of ancient volcanoes submerged during the era of Lake Minchin. They include unusual and fragile coral-like structures and deposits that often consist of fossils and algae.<ref name="trav1">{{cite book |last=Atkinson |first=David |url=https://books.google.com/books?id=WDBYHYwdhuAC&pg=PA174 |title=Bolivia: The Bradt Travel Guide |date=1 March 2007 |publisher=Bradt Travel Guides |isbn=978-1-84162-165-4 |pages=170; 174–176}}</ref>

===Climate===

The area has a relatively stable average temperature with a peak at {{cvt|21|°C}} in November to January, and a low of {{cvt|13|°C}} in June. The nights are cold all through the year, with temperatures between {{convert|-9|and|5|°C|°F|abbr=on}}. The relative humidity is rather low and constant throughout the year at 30% to 45%. The rainfall is also low at {{convert|1|to|3|mm|in|abbr=on}} per month between April and November, but it may increase up to {{convert|80|mm|in|abbr=on}} in January. However, except for January, even in the rainy season the number of rainy days is fewer than 5 per month.<ref name="ieee" />

{{Wide image|Gringo Trail banner Salar de Uyuni.JPG|1100px|{{center|During the rainy season (December to April) the flat turns into a shallow lake and becomes the world's largest natural mirror, featuring a reflection to the sky.}}}}

==Economic influence==
[[File:Parvas de sal, Salar de Uyuni, Bolivia - panoramio.jpg|alt=|thumb|Salt production at the salar]]
Located in the [[Lithium Triangle]], the Salar contains a large amount of [[sodium]], [[potassium]], [[lithium]] and [[magnesium]] (all in the chloride forms of [[Sodium chloride|NaCl]], [[Potassium chloride|KCl]], [[Lithium chloride|LiCl]] and [[Magnesium chloride|MgCl<sub>2</sub>]], respectively), as well as [[borax]].<ref name="trav1" /> As of 2024, with an estimated 23 mln.&nbsp;[[tonne|t]], Bolivia holds about 22% of the world's known lithium resources (105 mln. tons); most of those are in the Salar de Uyuni.<ref>{{cite news |url=https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-lithium.pdf
|title=Lithium Statistics and Information|publisher=[[USGS]]}} ([https://www.usgs.gov/centers/national-minerals-information-center/lithium-statistics-and-information other Lithium statistics from USGS])</ref>
[[File:Lithium brine extraction in the Salar de Uyuni salt flat, Potosí, Bolivia - 3 January 2023 (52616752619).jpg|thumb|[[Lithium]] brine extraction in the Salar de Uyuni]]
Lithium is concentrated in the brine under the salt crust at a relatively high concentration of about 0.3%. It is also present in the top layers of the porous [[halite]] body lying under the brine; however, the liquid brine is easier to extract, by boring into the crust and pumping out the brine.{{citation needed|date=June 2020}} The brine distribution has been monitored by the [[Landsat program|Landsat]] satellite and confirmed in ground drilling tests. Following those findings, an American-based international corporation has invested $137&nbsp;million to developing lithium extraction.<ref>{{cite book |url=https://books.google.com/books?id=j0QrAAAAYAAJ&pg=PA60 |page=60 |title=Science and technology for development: prospects entering the twenty-first century : a symposium in commemoration of the twenty-fifth anniversary of the U.S. Agency for International Development |publisher=National Academies |year=1988 |author=National Research Council (U.S.). Board on Science and Technology for International Development, National Research Council (U.S.). Office of International Affairs|isbn=9780309320023 }}</ref> However, lithium extraction in the 1980s and 1990s by foreign companies met strong opposition from the local community. Locals believed that the money infused by mining would not reach them.<ref name="BBC_electric_car">{{cite news |title=Bolivia holds key to electric car future |url=http://news.bbc.co.uk/1/hi/business/7707847.stm |website=[[BBC News|BBC]]|date=9 November 2008 }}</ref> The lithium in the salt flats contains more impurities, and the wet climate and high altitude make it harder to process.<ref>{{cite web |last1=Eisler |first1=Matthew |title=Bolivian lithium: why you should not expect any 'white gold rush' in the wake of Morales overthrow |url=https://theconversation.com/bolivian-lithium-why-you-should-not-expect-any-white-gold-rush-in-the-wake-of-morales-overthrow-127139 |website=[[The Conversation (website)|The Conversation]] |date=15 November 2019 |language=en}}</ref>

No mining plant is currently at the site, and the Bolivian government does not want to allow exploitation by foreign corporations. Instead, it intends to reach an annual production of 35,000&nbsp;t by 2023 in a joint venture with ACI Systems Alemania GmbH.<ref>{{Cite news |date=3 December 2018 |title=Bolivia's Almost Impossible Lithium Dream |url=https://www.bloomberg.com/news/features/2018-12-03/bolivia-s-almost-impossible-lithium-dream |access-date=26 March 2019 |newspaper=[[Bloomberg News|Bloomberg]]}}</ref><ref name="BBC_electric_car" /><ref name="ACISA">{{cite web |title=Lithium – ACI Systems Alemania GmbH |date=August 2019 |url=https://www.acisa.de/lithium/ |access-date=11 January 2020 |archive-date=27 June 2022 |archive-url=https://web.archive.org/web/20220627074037/https://www.acisa.de/lithium/ |url-status=dead }}</ref>

Salar de Uyuni is estimated to contain 10&nbsp;billion tonnes (9.8&nbsp;billion long tons; 11&nbsp;billion short tons) of salt, of which less than 25,000&nbsp;t is extracted annually. All miners working in the Salar belong to [[Colchani, Potosí|Colchani's]] cooperative. Because of its location, large area, and flatness, the Salar is a major car transport route across the Bolivian [[Altiplano]], except when seasonally covered with water.<ref name="nasa" />

==Tourism==

===Hotels===
{{See also|Palacio de Sal}}
[[File:Luna Salada Hotel 2017 01.jpg|thumb|A hotel in the Salar de Uyuni, built from salt blocks]]
Salar de Uyuni is a popular tourist destination, and consequently a number of hotels have been built in the area. Due to lack of conventional construction materials, many of them are almost entirely (walls, roof, furniture) built with salt blocks cut from the Salar. The first such hotel, named [[Palacio de Sal]], was erected in 1993–1995<ref name="lick2">{{cite web |date=27 January 2009 |title=Bolivian Hotel Truly Is the Salt of the Earth |url=http://www.hotelchatter.com/story/2009/1/26/231522/848/hotels/Bolivian_Hotel_Truly_Is_the_Salt_of_the_Earth |url-status=dead |archive-url=https://web.archive.org/web/20130515053921/http://www.hotelchatter.com/story/2009/1/26/231522/848/hotels/Bolivian_Hotel_Truly_Is_the_Salt_of_the_Earth |archive-date=15 May 2013 |access-date=16 October 2009 |work=hotelchatter.com}}</ref><ref name="lick1">{{cite web |date=19 May 2009 |title=Don't Lick the Walls of the Salt Hotel |url=http://www.tripcrazed.com/702316570/dont-lick-the-walls-of-the-salt-hotel/ |url-status=usurped |archive-url=https://web.archive.org/web/20090523140538/http://www.tripcrazed.com/702316570/dont-lick-the-walls-of-the-salt-hotel/ |archive-date=23 May 2009 |website=Tripcrazed.com}}</ref> in the middle of the salt flat,<ref name="lick3">{{cite web |last=McFarrren |first=Peter |date=4 March 1999 |title=Salt hotel has a rule: No licking |url=http://www.seattlepi.com/getaways/030499/salt04.html |publisher=The [[Associated Press]]}}{{Dead link|date=April 2023|bot=InternetArchiveBot|fix-attempted=yes}}</ref><ref name="book1">{{cite book |last1=Box |first1=Ben |url=https://archive.org/details/peruboliviaecuad00benb |title=Peru, Bolivia & Ecuador |author2=Kunstaetter, Robert |author3=Kunstaetter, Daisy |author4=Groesbeck, Geoffrey |publisher=Footprint Travel Guides |year=2007 |isbn=978-1-906098-06-3 |page=[https://archive.org/details/peruboliviaecuad00benb/page/378 378] |url-access=registration}}</ref> and soon became a popular tourist destination.<ref name="ng">{{cite web |date=25 July 2007 |title=Photo in the News: New Salt Hotel Built in Bolivia |url=http://news.nationalgeographic.com/news/2007/07/070725-salt-hotel.html |url-status=dead |archive-url=https://web.archive.org/web/20070728022241/http://news.nationalgeographic.com/news/2007/07/070725-salt-hotel.html |archive-date=28 July 2007 |access-date=1 September 2009 |publisher=The [[National Geographic]]}}</ref> However, its location in the center of a desert caused sanitation problems, as most waste had to be collected manually. Mismanagement caused serious environmental pollution and the hotel had to be dismantled in 2002.<ref>{{cite book |last=Adès |first=Harry |url=https://books.google.com/books?id=peBeMlMgcD4C&pg=PA259 |title=The Rough Guide to South America |publisher=[[Rough Guides]] |year=2004 |isbn=1-85828-907-6 |page=259}}</ref><ref name="german">{{cite web |title=Palacio del Sal |url=http://www.hbernreuther.de/Brasilien_Bolivien/Palacio_del_Sal/palacio_del_sal.html |url-status=dead |archive-url=https://web.archive.org/web/20081206050825/http://www.hbernreuther.de/Brasilien_Bolivien/Palacio_del_Sal/palacio_del_sal.html |archive-date=6 December 2008 |work=hbernreuther.de |language=de}}</ref>

Around 2007, a new hotel was built,<ref name="ng" /> under the name Palacio de Sal, in a new location 
at the eastern edge of Salar de Uyuni, 25&nbsp;km away from the town of [[Uyuni]].<ref name="book1" /> The sanitary system has been restructured to comply with the government regulations.<ref name="lick2" /> The hotel has a dry sauna and a steam room, a saltwater pool and whirlpool baths.<ref>{{cite web |title=Homepage of Palacio de Sal |url=http://www.palaciodesal.com/ |url-status=dead |archive-url=https://web.archive.org/web/20120226233554/http://www.palaciodesal.com/ |archive-date=2012-02-26 |access-date=2009-09-04 |language=Spanish}}</ref>

===Train cemetery===
One major tourist attraction is an antique train cemetery. It is {{convert|3|km|mile|abbr=on}} outside Uyuni and is connected to it by the old train tracks. The town served in the past as a distribution hub for the trains carrying minerals en route to Pacific Ocean ports. The rail lines were built by British engineers arriving near the end of the 19th century and formed a sizeable community in Uyuni. The engineers were invited by the British-sponsored Antofagasta and Bolivia Railway Companies, now [[Ferrocarril de Antofagasta a Bolivia]]. The rail construction started in 1888 and ended in 1892. It was encouraged by Bolivian President [[Aniceto Arce]], who believed Bolivia would flourish with a good transport system, but it was constantly interrupted by the local Aymara indigenous Indians who saw it as an intrusion into their lives. The trains were mostly used by the mining companies. In the 1940s, the mining industry collapsed, partly because of mineral depletion. Many trains were abandoned, producing the train cemetery. There are proposals to build a museum from the cemetery.<ref name="trav1" />

{{Wide image|Uyuni Décembre 2007 - Cimetière de Trains 1.jpg|1100px|Cemetery of trains near the town of [[Uyuni]]}}

===Incidents===
Multiple fatal incidents have occurred at the salt flat as a result of poorly maintained vehicles, untrained drivers, speeding, a disregard for the inhospitable conditions, and lack of regulation for tour companies. A total of 16 reported accidents have happened with 30+ deaths in total.<ref>{{cite web |title=Updated List of Accidents on Salar de Uyuni Tours - |url=https://www.uyuniguide.com/accidents-in-uyuni/}}</ref>

==Satellite calibration==
[[File:ISS059-E-517 - View of Bolivia.jpg|thumb|Satellite view of the Salar de Uyuni, located at the center of the image, captured from the [[International Space Station]].]]
As the largest salt flat on Earth, the Salar de Uyuni is widely regarded as one of the most effective natural calibration sites for [[Earth observation satellite|Earth-observing satellites]].<ref>{{cite journal |last1=Camargo Lamparelli |first1=R.A. |last2=Ponzoni |first2=F.J. |last3=Zullo |first3=J. |last4=Queiroz Pellegrino |first4=G. |last5=Arnaud |first5=Y. |date=June 2003 |title=Characterization of the salar de uyuni for in-orbit satellite calibration |journal=IEEE Transactions on Geoscience and Remote Sensing |volume=41 |issue=6 |pages=1461–1468 |bibcode=2003ITGRS..41.1461C |doi=10.1109/TGRS.2003.810713}}</ref> Its exceptionally high [[albedo]], which reflects the majority of incoming sunlight, together with its vast, uniform terrain, makes it uniquely well-suited for remote sensing applications.<ref>{{cite journal |last1=Borsa |first1=A. A. |last2=Bills |first2=B. G. |last3=Minster |first3=J. B. |year=2008 |title=Modeling the topography of the salar de Uyuni, Bolivia, as an equipotential surface of Earth's gravity field |journal=Journal of Geophysical Research: Solid Earth |volume=113 |issue=B10 |bibcode=2008JGRB..11310408B |doi=10.1029/2007jb005445 |article-number=2007JB005445}}</ref> Located at an altitude of {{convert|3650|m|ft|0|spell=}} above sea level, the salar offers stable [[emissivity]] and minimal [[Electromagnetic interference|radio frequency interference]], providing [[List of government space agencies|space‐agencies]] and remote sensing scientists with ideal conditions for calibrating both [[Radar Sensor|radar]] and [[Image sensor|optical sensors]].<ref>{{Cite web |year=2003 |others=[[Center for Earth Resources Observation and Science|EROS]] Cal/Val Center of Excellence |title=Test Sites Catalog - Uyuni Salt Flats |url=https://calval.cr.usgs.gov/apps/uyuni-salt-flats |website=[[United States Geological Survey]] |publisher=}}</ref> Across its {{convert|10582|sqkm|sp=us|adj=on}} surface, the elevation variation is less than {{convert|1|m|sp=us}} relative to the Earth's circumference. Collectively, these features make the Salar de Uyuni approximately five times more effective for satellite calibration than the surface of the open ocean.<ref name="gpsdaily">{{Cite news |date=29 November 2007 |title=The Hills And Valleys Of Earth's Largest Salt Flat |url=http://www.gpsdaily.com/reports/The_Hills_And_Valleys_Of_Earth_Largest_Salt_Flat_999.html |publisher=GPS Daily |publication-place=Oxford, United Kingdom}}</ref><ref>{{cite book |last=Spreen |first=Gunnar |url=https://books.google.com/books?id=CeLCxydgA8UC&pg=PA22 |title=Satellite-based Estimates of Sea Ice Volume Flux: Applications to the Fram Strait Region |publisher=GRIN Verlag |year=2008 |isbn=978-3-640-13064-1 |page=22}}</ref><ref>{{cite journal |last1=Bills |first1=Bruce G. |last2=Borsa |first2=A. |last3=Comstock |first3=R. |display-authors=1 |year=2007 |title=MISR-based passive optical bathymetry from orbit with few-cm level of accuracy on the Salar de Uyuni, Bolivia |url=https://zenodo.org/record/1259333 |journal=[[Remote Sensing of Environment]] |volume=107 |issue=1–2 |pages=240–255 |bibcode=2007RSEnv.107..240B |doi=10.1016/j.rse.2006.11.006}}</ref> 

In September 2002, [[NASA]]'s [[ICESat-2]] mission conducted extensive GPS surveys over the salar to support the calibration of its [[Lidar|laser altimeters]] and improve their capability to produce [[Ground truth|ground‐truth]] [[Digital elevation model|digital elevation models]] with centimeter‐level ({{sfrac|3|8}} inch) accuracy.<ref>{{cite journal |last1=Schutz |first1=B. E. |last2=Zwally |first2=H. J. |last3=Shuman |first3=C. A. |last4=Hancock |first4=D. |last5=DiMarzio |first5=J. P. |date=November 2005 |title=Overview of the ICESat Mission |journal=Geophysical Research Letters |volume=32 |issue=21 |bibcode=2005GeoRL..3221S01S |doi=10.1029/2005GL024009 |hdl=11603/24281 |hdl-access=free |article-number=2005GL024009}}</ref> Similar missions have been conducted over the Salar de Uyuni for radiometric calibration, where the [[Landsat 5|Landsat-5]] satellite's Thematic Mapper (TM) was calibrated “in-flight” by using the salar as a radiometrically stable target, particularly in the visible and near-infrared bands.

In April 2014, the [[European Space Agency]]’s (ESA) [[Sentinel-1A|Sentinel‑1A]] satellite surveyed the salar a few weeks after its launch as part of the [[Copernicus Programme|Copernicus programme]]. The mission focused on calibrating radar-based measurements of surface topography. In 2010, ESA launched the [[CryoSat-2]] mission to monitor variations in polar ice thickness and global sea levels. As part of its validation strategy, CryoSat-2 has relied on the salar, where its [[Interferometric synthetic-aperture radar|Interferometric synthetic-aperture radars]] (InSAR) capabilities were reinstated to enhance the precision of altimetric observations.<ref>{{Cite web |last1=Behnia |first1=S |last2=Wang |first2=T |last3=Sneeuw |first3=N |date=2018-09-29 |others=Institute of Geodesy |title=What can we learn from satellite altimetry over salt flats? A case study using CryoSat-2 over Salar de Uyuni |url=https://www.gis.uni-stuttgart.de/forschung/doc/Behnia_2018.pdf |access-date=2025-09-25 |publisher=[[University of Stuttgart]]}}</ref> In February 2024, the Copernicus [[Sentinel-3B]] mission conducted calibration activities over the salar for its [[Synthetic Aperture Radar|Synthetic Aperture]] [[Radar Altimeter]] (SRAL).<ref>{{cite journal |last1=Abileah |first1=R. |last2=Vignudelli |first2=S. |date=October 2021 |title=Precise inland surface altimetry (PISA) with nadir specular echoes from Sentinel-3: Algorithm and performance assessment |journal=Remote Sensing of Environment |volume=264 |bibcode=2021RSEnv.26412580A |doi=10.1016/j.rse.2021.112580 |doi-access=free |article-number=112580}}</ref>
==Flora and fauna==
The Salar is virtually devoid of any wildlife or vegetation. The latter is dominated by giant cacti (''[[Echinopsis]] atacamensis pasacana'', ''Echinopsis tarijensis'', etc.). They grow at a rate of about 1&nbsp;cm/a to a height of about {{convert|12|m|ft|abbr=on}}. Other shrubs include Pilaya, which is used by locals to cure [[catarrh]], and Thola (''[[Baccharis]] dracunculifolia''), which is burned as a fuel. Also present are [[quinoa]] plants and [[Polylepis rugulosa|queñua]] bushes.<ref name=trav1/>

Every November, Salar de Uyuni is the breeding ground for three South American species of [[flamingo]] feeding on local [[brine shrimp]]s: the [[Chilean flamingo|Chilean]], [[Andean flamingo|Andean]], and rare [[James's flamingo]]s. About 80 other bird species are present, including the [[horned coot]], [[Andean goose]], and [[Andean hillstar]]. The Andean fox, or [[culpeo]], is also present, and islands in the Salar (in particular [[Isla Incahuasi|Incahuasi Island]]) host colonies of rabbit-like [[viscacha]]s.<ref name=trav1/><gallery mode="packed">
File:FishIslandSalarUyuni.jpg|A part of [[Isla Incahuasi|Incahuasi Island]] inside the Salar, featuring giant [[cactus|cacti]]
File:James Flamingo.jpg|[[James's flamingo]]
File:Culpeo MC.jpg|[[Culpeo]]
File:Bolivian vizcacha.jpg|Bolivian [[vizcacha]]
File:Chloephaga melanoptera1.jpg|[[Andean goose]]
File:Andean Hillstar (Oreotrochilus estella) perched.jpg|[[Andean hillstar]]
File:Andean Flamingos Laguna Colorada Bolivia Luca Galuzzi 2006.jpg|[[Andean flamingo]]s in the [[Laguna Colorada]], south of the Salar
File:VicunaSalarDeUyuni 20170503.jpg|[[Vicuñas]] near the Salar De Uyuni 2017
</gallery>
==Gallery==
{{Wide image|Salar de Uyuni Décembre 2007 - Centre de Nulle Part.jpg|2000px|Panoramic view of the Salar.}}
<gallery mode="packed">
File:Salar de Uyuni 2013.jpg|Salar de Uyuni 2013
File:Piles of Salt Salar de Uyuni Bolivia Luca Galuzzi 2006 a.jpg|Piles of salt at the Salar
File:Salar Uyuni au02.jpg|Llamas in the Salar
File:Reflection on the Salar de Uyuni, bolivia.jpg|Reflection on the Salar de Uyuni
File:Salar de Uyuni lake.jpg|Sky reflections at sunset
</gallery>

== See also ==
* [[Ouki]]
* [[Puka Mayu (Potosí)|Puka Mayu]]
* [[Great Salt Lake]]
* [[Rann of Kutch]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category|Salar de Uyuni}}
* {{Wikivoyage-inline|Salar de Uyuni}}
*[https://www.salardeuyuni.com/ Salar de Uyuni official website]
* {{cite journal |last1=Goodale |first1=Mark |title=Of Crystals and Semiotic Slippage: Lithium Mining, Energy Ambitions, and Resource Politics in Bolivia |journal=Anthropological Quarterly |date=2024 |volume=97 |issue=2 |pages=361–386 |id={{Project MUSE|929493}} |doi=10.1353/anq.2024.a929493 }}

{{Altiplano lakes and paleolakes |state=expanded}}
{{Authority control}}

[[Category:Salt flats of Bolivia|Uyuni]]
[[Category:Landforms of Oruro Department]]
[[Category:Landforms of Potosí Department]]
[[Category:Endorheic lakes of South America]]
[[Category:Tourist attractions in Oruro Department]]
[[Category:Tourist attractions in Potosí Department]]
[[Category:Altiplano]]
[[Category:Second 100 IUGS Geological Heritage Sites]]