The travertine terraces of Mammoth Hot Springs in Yellowstone National Park sport multiple colors. The stark white color is from calcium carbonate, which is formed when limestone comes in contact with hot springs. To contrast with the white is a range of colors like orange and brown which are due to algae that live in warm pools. On the top is steam rising from Canary Spring, so named in the 1800s when it was dominated by sulfur dependent bacteria that gave it a canary yellow color.