Sue and Neal took Cathy's excellent Underwater photography course in the Cayman Islands.  The course lasts one week and you spend 3 hours at a time underwater taking pictures in the morning and all afternoon in class.

There are areas in New Guinea that are so volcanically active that football stadium sized sections of the ocean floor bubble continuously with sulfur dioxide gas, making it seem to divers like they're are swimming in a giant child's aquarium.