An estimated 10,500 athletes will participate in the 2012 Summer Olympics in London, with the host nation, Great Britian, sending 541 athletes to the games, more than anyone else, with Cyclist and four-time gold medal winner Chris Hoy as the flag bearer, followed by the United States (530, Mariel Zagunis), Russia (436, Maria Sharapova), Germany (391, Natascha Keller), China, France, Japan, Italy, Spain and Canada as the nations sending in the most athletes to London 2012.