In the early history of hockey, games were played outdoors on rivers, lakes, and other naturally occurring ice surfaces. In fact, the first indoor game, held in 1875, was a novelty at the time, yet after that the game moved inside. While the first Olympic hockey tournament, held in 1920, was played indoors, games at the first Winter Olympics in 1924 were the first of several such tournaments to be played outdoors. Games at the World Championships were occasionally played outdoors, including the 1957 gold medal game between the Soviet Union and Sweden at the Lenin Stadium in Moscow. The attendance at that game was approximately 55,000, a number that stood as a record for more than 40 years. In 1954, the Detroit Red Wings of the National Hockey League (NHL) played an exhibition game on an outdoor ice surface against the inmates of Michigan's Marquette Branch Prison.