The International Mathematical Olympiad (IMO) is the oldest and largest scientific Olympiad. During each of the two days of the competition, participants take a 4.5 hour, 3-question exam. The deceptively simple exam questions require much mathematical talent to solve. In July 2013, the 54th IMO was held in Santa Maria, Columbia. The United States came in third place behind China (1) and South Korea (2). For more information and a complete list of rankings, click here.