The original Olympic Games were held in Olympia, an ancient sanctuary in Greece.
The ancient games honoured Zeus and were traditionally dated from 776 BCE, although athletic contests at the sanctuary may have existed earlier. Olympia was located in the western Peloponnese, near the Alpheios River. Competitors and spectators travelled from many Greek communities for the festival, which took place every four years.
Events included footraces, wrestling, boxing, pankration, chariot racing, and the pentathlon. Participation was generally restricted to free Greek males, unlike the modern Olympic Games, which are international and include athletes of all genders. The ancient festival was connected to religious ceremonies as well as competition.
The Roman emperor Theodosius I is traditionally associated with ending the ancient games in the late fourth century CE. The modern Olympics began in Athens in 1896, so Athens is a common but incorrect answer to the question about the original ancient venue.