Poseidon Undersea Resort --Katafinga Island, Fiji
Currently under construction, this five-star resort will feature 22 guest rooms, an underwater restaurant and bar, a library, conference room, wedding chapel, and spa, and will be accessible exclusively via 16-person submarine that you can learn to drive while a guest.
Depth: 40ft
Rate: Register online to be notified when the resort begins taking reservations, which are a mere $30,000/wk per couple
Most exotic fish that'll stare disapprovingly at you through the glass: Fiji is teeming with tropical marine life, so be on the lookout for blue whales, bottlenose dolphins, wahoo (!), and colorful clownfish.