http://swissbaync5d7ykaz7dh7v4qjrb4gmen5aj3bogxrcgbb43ij34bjuyd.onion/pdf/Books/Survival/Medicine/oddsnends.htm
Seven Underwater Wonders of the World According to Rick Sammon, who has published a book by that name, they are: Belize Barrier Reef Lake Baikal in Siberia Norther Red Sea Galapagos Archipelago Austrailia's Great Barrier Reef Deep Ocean Vents of the Mid-Ocean Ridge Palau, a Pacific Archipelago Sammon's book contains full color photographs of each of these underwater wonders.
Interestingly, only one site, Belize, is convenient to North American divers.