Found in the mountain range of Serranía de la Macarena, the Caño Cristales river mesmerizes with amazing colors: yellow, green, blue, black and red shades quiver from the bottom. The liquid rainbow is caused by a unique phenomena: a red plant, Macarenia clavigera, growing in the riverbed. Other colors come from black rocks, green algae, blue water and yellow sand, producing an iridescent effect. The river also features waterfalls, pools and caverns, making it even more dramatic.