Bosphorus

The 31-kilometer strait dividing European and Asian Istanbul, the Bosphorus carries one of the world's busiest shipping lanes while also serving as a ferry corridor for the city's commuters. From the water, the succession of Ottoman mosques, wooden waterfront mansions called yalıs, Baroque palaces, and Genoese fortresses presents an unbroken panorama of six centuries of architecture. The Rumeli Hisarı fortress, built by Mehmed II in 1452 at the strait's narrowest point, is among the most dramatically positioned landmarks along the route.