Istanbul in the 1970s, as people from Anatolia migrated to the city to find employment in the many new factories that were built on the outskirts of the sprawling metropolis. This sudden, sharp rise in the city's population caused a large demand for housing, and many previously outlying villages and forests became engulfed into the metropolitan area of Istanbul. Istanbul is located in north-western Turkey within the Marmara Region on a total area of . The Bosphorus, which connects the Sea of Marmara to the Black Sea, divides the city into a European, Thracian side—comprising the historic and economic centers—and an
Korea Strait Korea Strait into the western channel and the Tsushima Strait. The western channel is deeper (up to 227 meters) and narrower than the Tsushima Strait. A branch of the Kuroshio Current passes through the strait. Its warm branch is sometimes called the Tsushima Current. Originating along the Japanese islands this current passes through the Sea of Japan then divides along either shore of Sakhalin Island, eventually flowing into the northern Pacific Ocean via the strait north of Hokkaidō and into the Sea of Okhotsk north of Sakhalin Island near Vladivostok. The water-mass characteristics vary widely because of the low-salinity waters