The splendid city of Istanbul has many unique and fascinating features. It is the only city in the world reaching across two continents, with its old city in Europe and modern Istanbul situated in Asia, separated by the Bosphorus Strait. It is also unique in having had capital status during two successive empires, Christian Byzantine and Islamic Ottoman, and the legacy from both is visible in the modern city today. Istanbul's location on the water made it a much coveted site as a commercial shipping port and military lookout, and as capital of the Roman Empire, Constantinople, as it was known, became extremely desirable as a centre of world trade, until Mehmet the Conqueror claimed it for the Ottoman Empire in 1453 and it became the imperial seat of the sultans. After the War of Independence the capital was moved to Ankara, but Istanbul still remains the commercial, historical and cultural heart of Turkey today. The charm and character of Istanbul lies in its endless variety and jumble of contradictions. Its fascinating history has bequeathed the city a vivid inheritance of Byzantine ruins, splendid palaces, ancient mosques and churches, hamams (bath-houses) and exotic bazaars. Modern Istanbul exudes trendy bars and nightclubs, western boutiques, office blocks, and elegant suburbs. The call to prayer heralds the start of each day and the city comes to life with over 11 million residents forming a chaotic social and cultural mix of unscrupulous carpet merchants, wealthy shoppers, religiously veiled women and destitute beggars. Joining the noisy throng are over-awed tourists and those capitalising on the tourist trade.