Grand Prismatic Spring, USA
The multi-coloured Grand Prismatic Spring is the largest hot spring in Yellowstone National Park in the USA. It is 90m across and over 50m deep.
The mineral-rich pool has concentric bands of vibrant colours from red to green, due to different sets of heat-loving pigmented bacteria in each band. The brilliant blue central part is extremely hot with temperatures reaching up to 87°C.
Spotted Lake, Canada
This is an alkaline lake rich in minerals, particularly sulphates, and contains small doses of silver and titanium. The circular spots appear during summer when most of the water evaporates.
Located in British Columbia, the lake is locally called Kliluk, and is considered sacred. During World War I, the lake's salts were used to make explosives.
Lake Retba, Senegal
Resembling a giant pool of strawberry pink lemonade, Lake Retba has very high levels of salt, so it is easy for people to float on its water. It also attracts salt harvesters.
The lake is near Senegal's Atlantic coast. It gets its brilliant pink colour from salt-loving microalgae called Dunaliella salina, which produce a red pigment to help absorb sunlight. The colour is especially prominent during the dry season.
Blood Falls, Antarctica
In the frozen wastes of east Antarctica, a bright-red cascading waterfall flows out of fissures in the Taylor Glacier. The water comes from a hyper-salty lake, which has been trapped beneath the glacier for 2 million years.
As the iron-rich water flows out, the iron reacts with oxygen in the air to form rust, giving the waterfall its vivid red colour. The ancient community of microbes in the lake could provide clues to life on prehistoric Earth and other planets.
Caño Cristales, Colombia
During a brief period between September and November, this river changes from ordinary clear water to a rainbow of colour. The vivid hues of red, blue, green and orange are caused by an endemic plant, Macarenia clavigera, blooming in the water - as well as mosses and algae.
The river is located in a remote part of the Serranía de la Macarena mountain range. It was closed off until the mid-2000s due to guerrilla activity.
Boiling Lake, Dominica
This lake literally boils and breathes out steam. It is located high up in Morne Trois Pitons National Park, and is accessible only by an arduous hike.
The lake is constantly heated by molten lava underneath, which vents steam and hot gas through an opening into the lake. Swimming here can be deadly.
Salar de Uyuni, Bolivia
This 10,582 sq km site is the world's largest salt flat. Hexagonal mesh-like patterns of salt, intermixed with salt mounds, dot the landscape.
During the wet season, the salt desert gets flooded by water from neighbouring lakes and transforms into a giant mirror reflecting the sky. The area is a major source of lithium.
Pamukkale Travertine Terraces, Turkey
Turquoise pools of water fill up limestone terraces, which were once deposited by flowing, mineral-rich hot springs.
Also called the Cotton Castle, the Pamukkale terraces lie next to the ancient Roman city of Hieropolis. Together, the terraces and city are a UNESCO World Heritage Site.
Pitch Lake, Trinidad
The black and viscous La Brea Pitch Lake is the largest natural deposit of tar or asphalt in the world. The lake is thought to lie between two faults, through which underground oil seeps up.
Tiny water droplets suspended in the tar are home to many microorganisms. The lake is also a treasure chest of fossilised animals that became entrapped in the sticky asphalt.
Loktak Lake, India
This lake is speckled by phumdis: large, circular masses of intertwined vegetation, soil and other organic matter. The largest phumdi covers over 40 sq km.
Rich in biodiversity, the lake is home to threatened animals like Indian pythons and hoolock gibbons. It also supplies water to a hydropower project.
Manicouagan Reservoir, Canada
Also called the "Eye of Quebec", Lake Manicougan formed when a meteorite struck the earth's surface several hundred million years ago.
The central part of the ring is raised, and its highest point is known as Mount Babel. The lake covers an area of almost 2000 sq km.
Plitvice Lakes, Croatia
Within a forested national park in Croatia, a series of 16 interlinked lakes cascade into waterfalls. The lakes are separated by natural limestone dams.
Declared a National Park in 1949, the Plitvice Lakes are a UNESCO World Heritage Site. The park has rich biodiversity, including rare animals like lynx, European polecats, and wolves.
Kelimutu Crater Lakes, Indonesia
Atop the Kelimutu volcano in Indonesia lie three crater lakes, each a different colour. The lakes are next to each other within the crest of the same volcano. They change their colours periodically, ranging from blue to green, red, black, and even chocolate brown or white.
The three lakes have different temperatures and chemical compositions.
Champagne Pool, New Zealand
Like in a glass of champagne, carbon dioxide gas constantly bubbles through the Champagne Pool. The hot spring formed about 900 years ago, and has a surface water temperature of about 74°C.
The vibrant orange edges of the pool are rich in silica, with deposits of arsenic and antimony sulphides. There are also deposits of mercury, thallium, gold and silver in the surrounding rocks.