The photo shows a diver moving in a flooded cave under the interface of salt and fresh water, which is called a halocline. Photographing near the halocline is very difficult because if the diver moves inappropriately, the salt and fresh water mix and visibility is almost zero from the photographer's perspective (look at the mixed water above the halocline in the picture). This image was taken while diving in the "Jardines del Eden - River Run" cave in Yucatan, Mexico. A total of five underwater flashes were used for lighting.