Track and Field

Meb Keflezighi

The Eritrean refugee won silver at Athens in 2004, six years after being naturalized as a U.S. citizen. In '14, a year after the Boston Marathon bombings, he become the first American to win that race in three decades. After his fourth-place finish in London, Keflezighi, 41, is striving to be the second American with two marathon medals. (Frank Shorter won gold in 1972 and silver in '76.)