Panathinaiko Stadium in Athens, Greece, was host to the first modern Olympic Games in 1896. Originally built ca. 566 BC, this stadium is home to a track with a shape quite unlike that of modern tracks. Rather than being divided into four equal segments of 400 meters (each straightaway is 100m long, as is each curve), the track at Panathinaiko Stadium is 200 meters long, with very sharp turns at each end.
The shape of this track harkens back to ancient chariot races, with long straightaways separated by a wooden or stone fence (rather than simply space, like a modern track) and dangerous hairpin curves. Because of its shape, it can’t be used for most running events (which require a standardized track) but it is often used as a concert venue and even held the finish line for the marathon in the 2004 Olympic games.
If you take a look to the west, you get a twofer: