Istanbul is a large Turkish city straddling Europe and Asia, separated by the Bosphorus Strait. Its old town reflects the cultural influences of the many empires that ruled Istanbul. In the Sultanahmet district, the open-air racetrack dating back to Roman times has hosted chariot races for several centuries, and Egyptian obelisks are still standing. The iconic Byzantine Hagia Sophia Museum features an imposing 6th-century dome and rare Christian mosaics