Istanbul

Istanbul carried the Byzantine and Ottoman empires for nearly fifteen hundred years between them, and the city is layered with both — Hagia Sophia is the cleanest single example, but the Basilica Cistern beneath, the Süleymaniye Mosque on the hill, the Grand Bazaar's 500-year-old vaults, and the Topkapı harem are the wider canvas. Cross the Galata Bridge at sunset and the ferries pass under your feet. Eat midye dolma on İstiklal at midnight. Take a ferry to Kadıköy on the Asian side for breakfast. The city earns the cliché — it really is two continents that talk to each other across a strait.