A rehearsal for the opening ceremony of the 15th IAAF World Championships is held at Chinas National Stadium， also known as the Birds Nest， in Beijing， on August 20.

Nearly 2，000 athletes from 207 countries and regions compete in 47 events during the biennial field-and-track competition on August 22-30. It is the first international sporting event Beijing has hosted since the 2008 Olympic Games.

The International Association of Athletics Federations also held its 50th congress in Beijing on August 19， where former British Olympic champion Sebastian Coe was elected president of the organization.