Bosporus

Satellite image of the Bosporus and Istanbul, taken from the International Space Station in April 2004

View of the Bosporus and Fatih Sultan Mehmet Bridge as seen from Rumelihisarı

The Bosporus or Bosphorus^[1] is a strait that forms part of the boundary between the European part of Turkey and its Asian part (Anatolia). It connects the Black Sea with the Sea of Marmara. It is about 30 km long, with a maximum width of 3,700 metres at the northern entrance, and a minimum width of 700 metres between Kandilli and Aşiyan; and 750 metres between Anadoluhisarı and Rumelihisarı. The depth varies from 36 to 124 metres in midstream.

The shores of the strait are heavily populated as Istanbul is located on each side. Three bridges and one tunnel cross the strait.

Bosporus Media

Location of the Bosporus (red) relative to the Dardanelles (yellow) and the Sea of Marmara
Aerial view of the Bosporus taken from its northern end near the Black Sea (bottom), looking south (top) toward the Marmara Sea, with the city center of Istanbul visible along the strait's hilly banks
Map of Constantinople (modern-day Istanbul), designed in 1422 by Florentine cartographer Cristoforo Buondelmonti. This is the oldest surviving map of the city, and the only surviving map that predates the Turkish conquest of 1453. The Bosporus is visible along the right-hand side of the map, wrapping vertically around the historic city.
The Bosphorus, with the Castles of Europe & Asia. 19th-century engraving by Thomas Allom. The castles are Rumelihisarı and Anadoluhisarı, respectively. The original is a watercolor available in the online collection of the Victoria and Albert Museum.
Modern (2012) view of the European side of Istanbul from the southern entrance to the Bosporus
15 July Martyrs Bridge (Bosphorus Bridge), the first to be built across the Bosporus, completed in 1973
Fatih Sultan Mehmet Bridge, the second crossing built in 1988, looking from the Asian side towards Rumelihisarı on the European side of the Bosporus
Yavuz Sultan Selim Bridge, the third and most recent crossing, in September 2016. The bridge was opened on 26 August 2016.
Russian fleet under the command of Admiral Fyodor Ushakov, sailing through the Bosporus