Several Olympic events for youth, like the European Youth Olympic Festival and the Australian Youth Olympic Festival have proven successful. The first concept of the Youth Olympic Games came from Austrian industrial manager Johann Rosenzopf in 1998, but the International Olympic Committee's response was negative. Jacques Rogge, IOC President, formally announced plans for the Youth Olympic Games in Guatemala, in 2007. In 2008 the city of Singapore was announced as the host of the inaugural Summer Youth Olympics in 2010. Over 200 countries and 3,600 athletes participated in the Youth Summer Olympics, in over 30 sports. The games are held every four years, and the age limitation of the athletes is 14 to 18.