The world's fastest zipline resides in Sun City, South Africa. They also claim it's the tallest and longest, but I think that's debatable. You ride the thing with a damn fin between your legs to keep you straight while reaching a top speed of 100 mph. Wow this thing is awesome, and it fulfills a lifelong dream of mine: To feel like you're about to die right before crashing into the South African desert and really dying. Awesome!
World's Fastest Zip Line Sends You Soaring [techeblog]