Pierre de Coubertin had the idea to bring back the modern Olympics in the late 1800s. He believed physical education should be an important part of life. He designed the Olympic flag featuring five rings to represent the five inhabited continents. Since 1896, 29 summer Olympics have been held in 22 cities, with London hosting three times and the United States hosting four times. The Olympic flame symbolizes fire being stolen from Zeus and is carried around host cities during the torch relay.