Mexico is home to some of the deepest, most complex cave systems in the world, but the Cenote Angelita is notable not only for its size but for its incredible underwater river systems.

If you aren't familiar with such a concept, you're probably wondering how a river can possibly appear under another body of water. The secret lies in the buoyancy of saltwater versus freshwater. In these caves, a thin level of hydrogen sulfate separates the freshwater up top from the saltwater below. The underwater trees that are only in the freshwater areas make the whole scene seem even more surreal, allowing for such mind-bending images as the one seen above by photographer Anatoly Beloshchin.