Diaulos (Greek: Δίαυλος, English translation: "double pipe") was a double-stadion race, c. 400 m, introduced in the 14th Olympiad of the ancient Olympic Games (724BC). 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 stadium at Olympia was 192.27 m but at Delphi it was 177.50 m 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 turning post, to prevent an outside runner from losing 3-4 m. These were called kampteres. Archaeological evidence at Nemea also shows that there were individual turning posts.