The lake sits about 44 metres below sea level in a dry valley in the south-west of the Dominican Republic. Because the water cannot flow out to the sea, the sun slowly evaporates it and the salt is left behind, making the lake saltier than most ocean water.
Isla Cabritos, a small island in the middle of the lake, is a national park. Rhinoceros iguanas - large, prehistoric-looking lizards - live there and are found almost nowhere else on Earth. They can grow over a metre long and have little bony bumps on their noses.
American crocodiles live all around the lake's edges. They are much shyer than their fierce reputation suggests, and they help keep the ecosystem healthy by controlling fish and other animal numbers.
Flocks of flamingos fly in to feed in the shallows. Their pink colour actually comes from the tiny shrimp and algae they eat - a baby flamingo is born white and only turns pink as it grows.