Organized athletics are traced back to the Ancient Olympic Games from 776 BCE. The rules and format of the modern events in athletics were defined in Western Europe and North America in the 19th and early 20th century, and were then spread to other parts of the world. Most modern top level meetings are conducted by the International Association of Athletics Federations and its member federations.
The athletics meeting forms the backbone of the Summer Olympics. The foremost international athletics meeting is the IAAF World Championships in Athletics, which incorporates track and field, marathon running and race walking. Other top level competitions in athletics include the IAAF World Cross Country Championships and the IAAF World Half Marathon Championships. Athletes with a physical disability compete at the Summer Paralympics and the IPC Athletics World Championships.