What was the name of the chariot-racing stadium in Constantinople?

The chariot-racing stadium in Constantinople was the Hippodrome of Constantinople.

The Hippodrome was far more than a racetrack. It was the sporting, political, and social centre of the Byzantine capital, with a U-shaped course, imperial viewing lodge, monumental decorations, and seating that may have accommodated around 100,000 spectators. The emperor could reach the Kathisma directly from the Great Palace.

Races were contested by factions, especially the Blues and Greens. These groups developed political and religious identities, and their rivalry sometimes became violent. The Nika riots of 532 began amid factional unrest at the Hippodrome and grew into a major revolt against Justinian I. The uprising destroyed much of Constantinople, including an earlier Hagia Sophia.

The Hippodrome was rebuilt and enlarged under Constantine the Great after he refounded Byzantium as Constantinople. Its central barrier displayed monuments such as the Serpent Column and the Obelisk of Theodosius. After the Fourth Crusade, the site declined. Today, much of it corresponds to Sultanahmet Square in Istanbul, where several ancient monuments still survive.