I've been really high before, but never THAT high.
Indoor Pool With 20M Diving Platform, Twice As High As Tallest Olympic Platform

This is a video of Tom Scott visiting the Montreal Olympic Sports Centre (built for the 1976 Summer Olympics), which features the only indoor 20-meter diving platform in North America. Apparently cliff diver Lysanne Richard convinced the Montreal Olympics Park to add an 18m platform in the rafters when the facility was undergoing renovations, and got them to add a 20m platform a few years later. 20 meters — that’s 65 feet! Apparently when you hit the water from that height you’re traveling at around 70km/h (~44MPH). That’s too fast. Me? I only jump off things that high in my dreams. Those dreams obviously being nightmares which I don’t survive.