The Chess Olympiad is a biennial tournament in which teams worldwide compete. It is held under the auspices of the World Chess Federation (FIDE) which selects the host nation. FIDE was established in 1924, the same year the summer Olympic Games was held in Paris. An attempt was made to include chess in the 1924 Olympic Games but it failed, because of the difficulty of distinguishing between amateurs and professionals. So, it was left to FIDE to organize a Chess Olympics. FIDE adopted the name Chess Olympiad and the first official team tournament was held in London, 1927. In 1924, there was an unofficial team tournament in Paris before FIDE was formed, which attracted 18 countries. After 1927, the Olympiads were held at irregular intervals until World War 11, but they have been held regularly since 1950. Any association or federation that is affiliated to FIDE may enter the Olympiad.