Where are the ancient olympic games believed to have originated?

Question: Where are the ancient olympic games believed to have originated?

The ancient Olympic Games were a series of athletic competitions among representatives of city-states and were one of the Panhellenic Games of Ancient Greece. They were held at the Panhellenic religious sanctuary of Olympia, in honor of Zeus, and the Greeks gave them a mythological origin. The originating Olympic Games are traditionally dated to 776 BC. The games were held every four years, or Olympiad, which became a unit of time in historical chronologies. They continued to be celebrated when Greece came under Roman rule in the 2nd century BC. Their last recorded celebration was in AD 393, under the emperor Theodosius I, but archaeological evidence indicates that some games were still held after this date. 

The ancient Olympic Games are believed to have originated in Olympia, Greece.