Since 1921, United World Wrestling (UWW) has regulated amateur wrestling as an athletic discipline, while professional wrestling has largely become infused with theatrics but still requires athletic ability. Today, various countries send national wrestling teams to the Olympics, including Russia, Iran, Turkey, Mongolia, Azerbaijan, Japan, South Korea, Gambia, the United States and several ex-U.S.S.R. nations. In Switzerland the local derivate of the German ringen, called schwingen, is a popular folk sport with local Schwingfest where regional competitions are played throughout the country.