A short video of Alex Honnold free soloing a 5.12 pitch halfway up 1500' wall.
You could say what he does is exceedingly dangerous - and you'd be correct. Except, here's a story of a climbing killed while bouldering in the gym.
"Mark Hesse, a long-time Colorado Springs resident, made numerous ascents of mountains, cliffs, and desert towers in his long and storied climbing career."
And here's a story of a climber killed by his partner. The guy who was killed was known for "hectoring fellow climbers with unsolicited advice on routes and holds.." So be careful out there folks; it's a dangerous world.