A salt lake is what happens when water flows into a basin and only leaves by evaporating. Everything dissolved in it stays, and over thousands of years the water becomes so dense that a human body cannot sink. The Dead Sea is about 34% salt against the ocean's 3.5%, which is why people float there reading a newspaper rather than swimming.
The same chemistry produces the other thing salt lakes are famous for. When a thin film of water sits on a perfectly flat salt crust, it becomes a mirror: no waves, no depth, no horizon. Salar de Uyuni is the largest and flattest surface on Earth — 10,500 km² varying by less than a metre — and after rain the sky lands on it completely. Satellite teams use it to calibrate instruments for exactly that reason.
So one heading covers two very different days out, and which one you get is a question of season and lake. Some are floats, some are mirrors, a few are both at different times of year. Three practical notes: salt water finds every cut you have, it destroys camera gear and shoes, and one lake on this list — Natron — is caustic enough that you do not go in at all.
Where on Earth it's best
1 Signature spotSalar de Uyuni
Potosí, Bolivia
The largest salt flat on Earth and the flattest place on Earth — 10,500 km² at 3,656 m with less than a metre of elevation variation across the whole surface. In the dry season it is a white hexagonal crust you drive across for hours with no reference points; in the wet season a few centimetres of water turn the entire thing into a mirror so complete that the horizon disappears and you appear to be walking in the sky. It holds somewhere between half and three-quarters of the world’s lithium reserves underneath, which is the other reason its name keeps coming up.
Nowhere else offers both states. The mirror only exists because the surface is flat enough for water to sit evenly across a hundred kilometres.
When · Mirror: January to March, after the summer rains — March is usually the sweet spot. Dry crust and hexagons: May to November. Sunrise and sunset are when the mirror does its work.
View details 2Dead Sea
Balqa, Jordan
The water covered 1,050 square kilometres in 1930 and about 605 now, and as it withdraws the ground behind it collapses: sinkholes have opened in swarms on both shores since the early 1980s.
The lowest land on Earth at −430 m, and about ten times saltier than the ocean. You do not swim, you sit — the water pushes back hard enough that lying on your front is difficult and turning over is a manoeuvre.
When · Year-round; March–May and September–November are comfortable. Summer passes 40 °C at the lowest place on the planet.
View details Lake Tuz
Aksaray, Türkiye
The water across its 1,665 square kilometres is normally about 40 centimetres deep — shallow enough that in October 2021 the lake dried out completely.
Anatolia's own version of both states: a shallow mirror in spring, and by August a dry salt pan turning pink from the halophilic algae that live in the brine. It supplies most of Türkiye's table salt.
When · Mirror in April–May while there is still meltwater on it; pink and dry from July to September; flamingos breed on it in summer.
View details Laguna Cejar & Salar de Atacama
Chile
You float in a sinkhole lagoon sunk into the salt flat that supplies roughly a third of the world's lithium carbonate, in a basin where the rain averages under 30 millimetres a year.
A chain of brine lagoons inside the Atacama salt flat, salty enough to float in, at 2,300 m with volcanoes on the skyline and flamingos on the far side.
When · Year-round. Mornings are calm; afternoons bring wind across the flat.
Great Salt Lake
United States
A railway causeway built in the 1950s cut the lake in two, and the saltier north arm now runs pink from Dunaliella salina and salt-loving archaea while the south side stays green.
The largest salt lake in the western hemisphere, salty enough to float in, with Robert Smithson's Spiral Jetty — a 460 m earthwork built in 1970 — on its north arm, visible or submerged depending on the water level.
When · May to October. The jetty is exposed at low water, which since 2020 has been most of the time.
Salinas Grandes
Argentina
The crust averages 30 centimetres thick and formed over five to ten million years from volcanic salts washed into a basin with no outlet: you walk on the residue of a vanished lake.
A 200 km² salt flat at 3,450 m on the road between Jujuy and the Atacama, quartered by salt-cutters into geometric pools of turquoise brine you can walk between.
When · Dry and walkable May to November; a thin mirror forms in the summer rains, January to March.
Lac Rose (Lake Retba)
Dakar, Senegal
A lagoon worked by salt collectors who stand chest-deep in it all day with shea butter on their skin as protection. Its strawberry-pink Dunaliella bloom failed after the floods of September 2022 and has only partly returned.
When · Pinkest from November to June, in the dry season and strongest around midday sun.
View details Lake Assal
Tadjoura, Djibouti
Its water arrives from the sea, seeping through fissures from the Ghoubbet across a rift that opened by 2.4 metres in a single week when Ardoukoba erupted in November 1978.
The lowest point in Africa at −155 m and the saltiest lake outside Antarctica — around 35% salt, ringed by a white crust and black lava, with camel caravans still cutting salt from the shore.
When · November to February. The rest of the year regularly exceeds 45 °C.
View details Chott el Djerid
Tozeur, Tunisia
France surveyed this basin between 1869 and 1892 for a canal meant to flood it into an inland sea; nothing was dug, and the chott floor still lies 15 to 25 metres above the Mediterranean.
A 7,000 km² salt pan that produces some of the most convincing mirages anywhere — the causeway across it appears to run into open water that is not there. Parts of Star Wars were filmed on its edge.
When · Dry and crusted from May to October, with the strongest mirages in summer heat; a shallow flooded layer forms in winter.
View details Lake Natron
Arusha, Tanzania
Sixteen kilometres south stands Ol Doinyo Lengai, the only volcano on Earth now erupting carbonatite: lava so cool, 540 to 593 °C, that it turns white within hours.
The lake you do not get into. Its alkalinity reaches pH 10.5 and it can hit 60 °C, which kills almost everything — and yet it is the only regular breeding site for East Africa's 2.5 million lesser flamingos, because nothing else can reach their nests.
When · Flamingo breeding builds from August to October; the lake is at its most colourful in the dry season.
View details