Muhammad Ali vs Wilt Chamberlain ???? July 26, 1971 – Houston Astrodome
It was in 1971, though, that it looked like this throwdown was really going to finally happen. Wilt signed a contract to fight Ali at the Houston Astrodome on July 26, 1971, potentially for the heavyweight title if Ali could beat champion Joe Frazier that March. However, Ali dropped the Frazier fight for his first professional loss, and Chamberlain ended up backing out at the last minute thanks to an escape clause in his contract.