Labadee in Haiti has the longest over-water zip line in the world: Dragon’s Breath Flight Line. It’s quite high, and you end up going quite fast. The zoom on my camera may obscure just exactly how high and long the zip line is, so here are the numbers: it is 2,600 feet long and 500 feet high. You end up reaching speeds of 40 to 50 miles per hour! You can read the detailed account here.
Royal Caribbean has outfitted some of its bigger ships with a zip line. The zip line is quite high: 9 decks high to be precise. It’s also about 80 feet long. It’s not the same as zip line for real where you have multiple legs, but as close as you’ll get on a cruise ship! You have to remember to have laced shoes with socks and your clothes can’t be wet. You can read the detailed account here.