Reebok Spartan Races, Boston

Modern Spartans wage a battle against the limits of their athletic abilities. Extreme athletes banded together to design Reebok Spartan Races' intense courses, resulting in races strewn with more than 20 signature obstacles. These natural and man-made tests challenge mind-body fitness, resilience, stamina, and strength, and are designed to leave participants both exhausted and exhilarated. What started as a single race in 2010 has now grown to more than 130 races across 20 countries.