Lake Retba, known as the "Pink Lake" is located 30 km north-east of Dakar, the capital of Senegal and is about 3 km² in size. It is only a few hundred meters from the Atlantic Ocean and is surrounded by dunes and filaos.

This lake is known for its high salt content. Indeed, it contains an extreme density of salt, nearly 400 g of salt per litre. Hard to imagine, isn't it? To give you an idea, the salt content of the Dead Sea is 275 grams per liter and that of the ocean is 35 grams. A large salt mining operation website has been in place for decades to extract the salt, and they export around 50,000 tons per year to all parts of the world.

"And its pink color? " you might say, well, the explanation is scientific.

In fact, the lake is inhabited by a cyanobacterium - a collection of bacteria called "blue algae" and "blue-green algae", which are composed of chlorophyll and other pigments. Usually the colour of the water where these bacteria nest is blue in 50% of cases - a microscopic organism that produces a red pigment to resist the high concentration of salt. These bacteria produce pigments in greater or lesser quantities depending on the wind and solar radiation, resulting in a greater or lesser intensity of the pinkish colour of the lake.