Extract all the place names from the paragraph. Different places should be separated by comma.

Context: London was the first city to host the Summer Olympic Games three times. As of 2022, Paris, Los Angeles, Athens and Tokyo have each hosted twice; Paris will host for the third time in 2024, followed by Los Angeles which will host the Games in 2028. Only five countries have participated in every Summer Olympic Games: Australia, France, Great Britain, Greece, and Switzerland. Australia, France and Great Britain have won at least a medal at every edition of the Games, with Great Britain as the only one to win gold each time. The United States leads the all-time medal count at the Summer Olympics, and has topped the medal table on 18 separate occasions—followed by the USSR, and France, Great Britain, Germany, China, and the ex-Soviet 'Unified Team'.

Answer: Paris, Los Angeles, Athens, Tokyo, Australia, France, Great Britain, Greece, Switzerland, Australia, France, Great Britain, USSR,Germany, China