Caption: The main gate of the Olympic Village in Beijing, China
The Olympic Games consist of a wide variety of competitions between athletes from all over the world. The Winter and Summer Games currently alternate on even-numbered years. The Games are held at a different site each time. That's an awful lot of planning to be done.
How is a site chosen? The International Olympic Committee chooses. A city that wishes to be considered to host the Olympic Games must submit a proposal. The IOC reviews all of the cities' proposals. A vote is held about six years before the Games will be held. Majority wins. If there's not a majority vote for one city right away, a revote is held, eliminating the lowest-voted city until there's a majority. Committee members take into account the best ideas for facilities, the city which appears best able to carry out the plans, and places that haven't been chosen before. When a city is chosen to be a host city, the local organizing committee pays to carry out the plans. The host city counts on TV revenues, ticket sales, and so on to pay for this expensive undertaking.