If base jumping on land isn't really your cup of tea, why not try it underwater? Guillaume Nery did just that, and it was all filmed on breath hold by Julie Gautier. Nery takes a big leap and base jumps underwater into Dean's Blue Hole near Long Island, Bahamas. It's the world's largest blue hole, reaching 663 feet down. A blue hole is a water-filled sinkhole with the entrance below the water level, and they're obviously just perfect for some zero-gravity base jumping.