Every 4 years there is a big event, an event which brings everyone together to celebrate whatever sport they are best at. Many people also join to support the athletes. These games are called the Olympics.
Many people take part in these vigorous games, however, all these athletes need somewhere to stay. That is why the Olympic park was built. It is basically a university campus but full of the best, up-and-coming athletes in the world. Each country has its own dorm area and they are called upon for practice early each morning.
Their coaches stay in separate dorms but in the same areas so that they can call the athletes for all night practices or early morning exercise.