Once the social and sporting center of Byzantium, the ancient Hippodrome is now part of Sultanahmet Square and has been a UNESCO World Heritage Site since 1985.
It is located between Hagia Sophia and Blue Mosque and was the scene of many sporting contests, ceremonies, public entertainment and social events, even during the time of the Ottomans.
Only a few ruins of the Hippodrome (Turkish Hipodrom or At meydanı) bear witness to the former glory of the racetrack, built by Emperor Septimius Severus in 203. Emperor Constantine I expanded the complex into one of the largest racecourses in the world based on the Circus Maximus in Rome. After the expansions, the racetrack was 429 meters long and 119 meters wide. Its stands had a capacity of approximately 100,000 spectators.
On the former site of the Hippodrome were three columns.
> The Three-headed Serpent, the sacrificial altar of Plataea, stood in front of the Temple of Apollo in Delphi. Constantine I brought it to Constantinople in 331 to decorate his new capital. After the conquest of Constantinople by the Ottomans in 1453, one of the heads was damaged. Today, all that is left is a part of the base of the Serpent Column (Yılanlı Sütun).
> The ancient Egyptian obelisk of Pharaoh Thutmose III comes from the temple of Karnak in Luxor and was brought to Constantinople in 390 by Emperor Theodosius I. The Obelisk of Theodosius (Dikilitaş), as it has since been called, was originally 30 m high. However, it was already damaged in ancient times. The upper part is still preserved. The marble pedestal is an important monument of the Theodosian period. Relief ornaments showing various situations of imperial self-expression can be seen on all four sides.
> A 32-meter high obelisk from the reign of Emperor Constantine VII (913-959) was once covered with beautiful copper and brass plaques. Today only the core of the column is visible. That is why it is called the Walled Obelisk (Örme Dikilitaş). During the Fourth Crusade at the beginning of the 13th century, the plaques of the column were stolen. Later, it suffered further damage by a devastating earthquake in 1894.