Tournament of Towns

From Wikipedia:

The Tournament of the Towns (International Mathematics Tournament of the TownsТурнир ГородовМеждународный Математический Турнир Городов) is a town-based mathematics contest originating in Russia. The contest was created by mathematician Nikolay Konstantinov and has participants from over 100 cities in many different countries.

Official cite (Moscow, English)

Tournament of Towns @Toronto