Istanbul is a major city in Turkey that bestrides Europe and Asia beyond the Bosphorus Strait. It is Old City that reflects the cultural impacts of the many empires that once ruled here. In the Sultanahmet region, the open-air, Roman-era Hippodrome was for centuries the chariot races’ site. Egyptian obelisks also survive. The iconic Byzantine Hagia Sophia highlights a soaring 6th-century arch and rare Christian mosaics.