I, personally, have never been snow skiing but I'm told it's not easy. That why this video just fascinates me. I've probably watched it 10 times already trying to figure out exactly how they pulled this off.

There are 30 skiers, holding hands, all doing back flips at the same time. It almost comes off as a 'wave' of sorts. They all stay connected and land perfectly. No one falls, no one breaks the chain. It's incredible.