The International Mathematical Olympiad (IMO) is the World Championship Mathematics Competition for High School students and is held annually in a different country. The first IMO was held in 1959 in Romania, with 7 countries participating. It has gradually expanded to over 100 countries from 5 continents. The IMO Advisory Board ensures that the competition takes place each year and that each host country observes the regulations and traditions of the IMO.

The international office of IMO is hosted at CWI, the Centrum Wiskunde & Informatica (CWI). In 2011 the International Mathematical Olympiad was organized in Amsterdam, the Netherlands. CWI also supported this event, not only for the participants but also in order to stimulate the public interest for mathematics. For an impression of IMO 2011, see: http://www.imo2011.nl/

More information on IMO: http://www.imo-official.org/