The Great Lakes were not always the size they are today. Around 9,000 years ago, parts of what is now the bottom of Lake Huron were dry land. And beneath what is now 120 ft (37 m) of water, Mesolithic Americans once hunted caribou there. 1/n

There is physical evidence that humans were there too. Excavation of the submerged site recovered more than a dozen chipped-stone flakes, including several from inside the hunting blinds. They appear to be debris from making or repairing stone tools. 8/n

This isn't AI, nor the set for a children's TV show. This is 'Spotted Lake' in Canada. As water evaporates in summer, the lake separates into blue, green, yellow and white mineral pools, each with a slightly different chemical makeup. 1/3

It lies near Osoyoos in British Columbia and is extremely rich in minerals, including magnesium sulphate, calcium and sodium sulphates. As summer heat removes the water, those minerals crystallise and concentrate into separate pools, producing the lake’s extraordinary spotted appearance. 2/3

There is a lake in Australia that is bubblegum pink. Not just around the edges, and not because of algae floating on top. The entire lake, and even water taken from it, stays vividly pink. But why does Australia's Lake Hillier have the bizarre colour? 1/4

Its colour comes from the strange chemistry of an extremely salty lake. Microbes that thrive in brine, including Salinibacter ruber and the alga Dunaliella salina, produce red and pink pigments. Together, they tint the whole body of water. 3/4

This animal wasn't discovered until 1992. It only came about by chance, when scientists surveying a nature reserve found unusual horns in hunters’ houses. The ‘Asian unicorn’ is one of the most elusive mammals on Earth. 1/5

It lives in dense, wet forest along the Annamite Mountains on the Vietnam-Laos border. The species is now "Critically Endangered", and experts think there may be fewer than 100 left. 4/5