This video will probably be the craziest thing you see today.
In it, professional skydiver Alexander Polli jumps out of a helicopter and flies through a narrow hole in a rock wall while wearing only a wingsuit, a fabric outfit that lets humans "fly." (Think of a flying squirrel, and you'll get the picture.)
The video was shot in high-definition by many cameras, including a helmet cam, to give the viewer an idea of what it's like traveling at speeds of up to 155 mph through an opening in a sheer rock wall.
When he tweeted the footage Wednesday, Polli wrote a short but profound message to go along with the video: "I live like this because I am aware I have only 1 life."
As for how Polli landed, we're hoping that tiny backpack he's wearing is a parachute.
(Hat tip, Mashable)