The Bosporus or Bosphorus, also known as the Strait of Istanbul, is a narrow, natural strait and an internationally significant waterway.
The width of the Bosphorus varies from 500 meters to 3 km, and the depth from 50 to 120 meters.

The southernmost Bosphorus Bridge (Boaziçi Köprüsü), the central Mehmet the Conqueror Bridge (Fatih Köprüsü), the Marmaray Railroad Tunnel, and the Yavuz Selim Bridge all span the Bosphorus.
  There is no other city on the planet where you can see two continents from the same vantage point. Istanbul is a metropolis that stretches across the Bosphorus and boasts a breathtaking perspective.  The Bosphorus has spectacular and distinctive scenery with its boats, dolphins that cheerfully leap over the sea, and seagulls that amazingly dance in the air.

  The Bosphorus, which was once known by the name Bosphore, adopted the word Bosphorus, and went so far as to become the definition of the word Bosphorus, just as Rome was once referred to with vague names such as urbs or kent, and was still distinguished from other settlements, cities, and other parts of the world. Because of the basalt columns and caves at the Bosphorus’s terminus, the ancient Greeks named it Symplgades, which means “Clashing Rocks.”

  The following is the most well-known Bosphorus legend, which is also cited in several MYTHS:
Zeus fell in love with the mortal Io and turned her into a cow to shelter her from Hera’s fury. Hera, on the other hand, learns of this and summons a fly to chastise and harass Io. Io runs towards the coasts of the Bosphorus from Europe, gets into the icy waters of the Bosphorus, and begins to swim across while being pursued by the fly. On this occasion, the Bosphorus may have been used for the first time to cross from one continent to another.

   Even if you are not an explorer, the Bosporus will arouse your yearning for discovery, the thrill of crossing continents, and the pleasure of an intercontinental journey.
 In Istanbul, the paths through the Balkans and the Anatolian Peninsula are linked without encountering any significant obstacles. The Bosporus’ function as a sea route connecting the cultural realms of the Black Sea and Mediterranean regions, as well as the connection of roads that bring Asia and Europe together towards the Bosporus, are important factors that give Istanbul a distinct personality and have influenced the city’s development throughout history.