More than you. A trampoline is best. A 3m springboard set on minimum bounce is fun too, or a 5m platform but those are uncommon. I was at a place that had a 7.5m and 10m, but I never did anything but jump normally off those. There are some bluffs around where I live that have a 20ft, 40ft, 60ft, 70ft "max air" where you have to run off to clear the 40ft bluff below it, and a rarely-hit 110ft (!!!) About 15 people have died at these bluffs, usually from drinking or getting knocked out on impact, and sinking immediately as the cliff continues 100 feet underwater below the bluffs.