One of the most extraordinary swimmers of all-time, Duke Kahanamoku wasn't even a swimmer by trade because he arguably made an even bigger impact in the popularization of surfing. Kahanamoku won a gold medal in the 100m freestyle in 1912 and took down prominent silver medals in both 1920 and 1924. Ultimately, Duke would lend his name and legacy to a series of restaurants that have become popular hot spots in Hawaii and California.