International Mathematical Olympiad, Cluj-Napoca, 3 - 14 July 2018 (home page)
The International Mathematical Olympiad (IMO) is the largest, oldest and most prestigious scientific Olympiad for high school students. The history of IMO dates back to 1959, when the first edition was held in Romania with seven countries participating: Romania, Hungary, Bulgaria, Poland, Czechoslovakia, East Germany, and USSR. Since then, the event has been held every year (except 1980) in a different country. Currently, more than 100 countries from 5 continents participate. Each country can send a team of up to six secondary students or individuals who have not entered University or the equivalent, as of the date of celebration of the Olympiad, plus one team leader, one deputy leader, and observers if desired.