The Ice Hockey World Championship is an annual international men’s ice hockey tournament. It is the highest-profile tournament of its kind. The championships are organized by the International Ice Hockey Federation (IIHF) whose headquarters are in Zurich, Switzerland. Founded in 1908, the federation maintains the IIHF world rankings as well as administrating yearly ice hockey tournaments. While the European Championships were first held back in 1910, it was during the 1920 Summer Olympics in which the first internationally recognized Ice Hockey World Championships took place. From that time up until the year 1968, the victor of the Olympic hockey tournament was considered that year’s world champion in hockey. Originally the tournament consisted of only amateur players. That is until a ruling in 1977 allowing professional athletes to take part in the tournament was passed. Players are required to play for the country that they are citizens of, although they are granted the ability to switch national teams if they’ve participated in at least two consecutive hockey seasons and 16 consecutive months for that given country. The current IIHF World Championship format consists of 16 teams divided into two groups of the preliminary round. The seeding is based on IIHF world rankings. The eight winners of the preliminary round face-off in the playoff medal round, where the victor is crowned world champion.