Pic shows underwater fog in Mexico, photographer says 'It's like another world'

Divers exploring the caverns of Mexico shared photos of the descent into swirling fog caused by alternating layers of fresh water and salt water, creating the illusion of a river underwater. Underwater photographer Francis Perez dived into a cenote called 'El Pit' in Yucatan, Mexico. "It's like flying over a river...It's like another world, a mysterious place," said Perez.