I've spent a lot of time in Yosemite over the years. On our first hike up to the top of Half-Dome in the 1980s, we were going up the rope-ladder and I was just about to the top when all of sudden I saw a guy jump off the top into the air over the Valley! I thought jeez what a way to commit suicide. But as we looked over, we saw that he actually had a parachute and was OK. He was simply base-jumping, but it sure gave us a scare! Base-jumping is not allowed anymore.