Black Pool is a hot spring at the West Thumb Geyser Basin at Yellowstone National Park. It is named Black Pool because it was once black. But in 1991, the water got super-heated killing the cyanobacteria responsible for its blackish color and it became this beautiful clear blue color. Black Pool is still extremely hot and one of the prettiest and intensely blue pools in the park.
Picture of the Week
edge detail, Black Pool, Yellowstone, Wyoming