Every four years, the Summer Olympics takes place in a different city around the world. The location is not the only thing that has changed over time. Many of the sports included in the Olympics have changed too. Occasionally, new sports are added. Many sports have been removed. From 1900-1920, tug of war was an official Olympic event. In 1908, powerboat racing was as well. In the early 1900s, polo matches were part of the Olympic Games. Not anymore. Polo .....