Every sport needs a rivalry to help it grow.  In the young sport of the triathlon, the first one of note was between Dave Scott and his younger challenger, Mark Allen, who won a record six Ironman World Championships.

We have other nominated athletes who transcended sports, but there is still only one Muhammad Ali.

Women's soccer in the United States didn't begin with Michelle Akers, but we think she was the one who told her country that it arrived.