To do this I have in the past 24 hours I have taken the opportunity to examine what has become of previous Olympic Stadia, dating back to 1960 when the summer games were held in the eternal city, Rome.

FORBES: Olympic Meddle

On Friday, the three-time heavyweight champion, whose name became synonymous with the phrases "float like a butterfly, sting like a bee" and "I am the Greatest, " made another memorable appearance late Friday during a spectacular opening ceremony ushering in the 2012 Summer Olympic Games in London.

CNN: STORY HIGHLIGHTS