3. Mark Spitz
Despite the fact that Michael Phelps won more medals in the 2008 Olympics, it could easily be argued that Mark Spitz's 1972 Olympics were the most impressive by any Olympian ever. Not only did Spitz win seven gold medals in the seven events he competed in, he also set the world record in each event.
In addition to his unforgettable 1972 performance Spitz also won two golds, a silver, and a bronze in the 1968 Games. After the Munich Olympics, Spitz retired from competitive swimming at the young age of 22. Had he continued his career and competed in the 1976 Games who knows how many more records he may have set.
And let’s not forget his mustache, which is probably worthy of a gold medal of its own.