The Bosphorus, Istanbul, Turkey . It is not a river, it is a "waterway" linking two seas the Black Sea to the Marmara Sea. 8,000 years ago, it was land, and the Black Sea was a very large lake . On the left is Europe or Avrupa, on the right is Asia or Anadolu, and the bridge obviously links the two continents, the only one that does that in the world . Make sure to take a public ferryboat ride up and down the Bosphorus.