Istanbul is a city in Turkey that straddles Europe and Asia across the Bosphorus Strait. The Old City reflects cultural influences of the many empires that once ruled here. In the Sultanahmet district, the open-air, Roman-era Hippodrome was for centuries the site of chariot races, and Egyptian obelisks remain. The iconic Byzantine Hagia Sophia features a soaring dome and Christian mosaics. Founded on the Sarayburnu promontory around 660 BCE as Byzantium, the city now known as Istanbul developed to become one of the most significant cities in history. The city is the administrative center of the Istanbul Metropolitan Municipality hosting a population of around 14 million residents. Istanbul has numerous shopping centers, from the historic to the modern. The Grand Bazaar, in operation since 1461, is among the world's oldest and largest covered markets. Istanbul has many historical and beautiful sites for the tourist, many are walkable but the transport network is also good around the city.