Diaulos (Greek: Δίαυλος, English translation: "double pipe") was a double-stadion race, c. 400 metres (1,300 feet), introduced in the 14th Olympiad of the ancient Olympic Games (724 BC). The length of each foot race varied depending on the length of the stadium. This was because the Greek foot varied widely from one locality to another, for example the stade at Olympia was 192.27 metres (630.81 feet) but at Delphi it was 177.50 metres (582.35 ft) long. Scholars debate whether or not the runners had individual "turning" posts for the return leg of the race, or whether all the runners approached a common post, turned, and then raced back to the starting line. Although at Delphi an inscription referenced "turning-posts" as opposed to "turning-post" which suggests each runner had their own tur