Photographing the Caves of the Yucatan
Underwater photography in general, but even more so in cenotes, caves, or wrecks, requires a special kind of effort along with the most demanding safety standards; lighting in such environments is, except very rarely, artificial and must be set up by a pro all the while coordinating (non-verbal in the silent world) with the photographer. The model thereafter must place themselves in the indicated area, have an impeccable buoyancy, make sure not to exhale under the decorations (stalactites) nor have any physical contact whatsoever with the cave or surroundings... More here.
The amount of work and skill to capture even one photo in a place like this is extraordinary. I can't get my mind around the time and effort needed, but remain impressed all the same.