Next, the Olympic flag is carried horizontally (since the 1960 Summer Olympics) into the stadium and hoisted as the Olympic Hymn is played. The Olympic Charter states that the Olympic flag must "fly for the entire duration of the Olympic Games from a flagpole placed in a prominent position in the main stadium". At most games, the flag has been carried into the stadium by prominent athletes of the host nation, but in 2012, it was carried by an international group of athletes and non-athletes famous for promoting Olympic values, including Muhammad Ali as a symbolic flag-bearer.