The 1906 Intercalated Games or 1906 Olympic Games was an international multi-sport event that was celebrated in Athens, Greece. The Games were held from April 22 to May 2, in Athens, Greece. They took place in the Panathenaic Stadium, the only stadium in the world built entirely of marble. The 1906 games were quite successful. Unlike the 1900, 1904 or 1908 games, they were neither stretched out over months nor overshadowed by an international exhibition. Their crisp format was most likely instrumental in the continued existence of the games. These Games also were the first games to have all athlete registration go through the NOCs. They were the first to have the Opening of the Games as a separate event: an event at which for the first time the athletes marched into the stadium in national teams, each following its national flag. They were also the first with an Olympic Village, at the Zappeion. They introduced the closing ceremony, the raising of national flags for the victors, and several less visible changes now accepted as tradition.