There are plenty of dramatic knockouts from which to choose. Marciano recovering from being knocked down for the first time in his career to beat Walcott; Last year's classic between Corrales and Castillo; Foreman becoming the oldest to win a heavyweight title; and Buster Douglas shocking Mike Tyson are just a handful of the options.
It's quite a list to narrow down, but there's only one #1! Vote for your top five knockouts of all-time, then watch "Who's #1?: Greatest Knockouts" on ESPN Classic on Wednesday, September 20 at 10 p.m. ET!