Istanbul, Turkey, the largest city in Turkey and the industrial, commercial, and cultural center of the nation. Istanbul, formerly the capital of the Byzantine Empire and later of the Ottoman Empire, was for centuries one of the world's preeminent cities.

Istanbul lies partly in Europe and partly in Asia on the traditional land route between Europe and Asia Minor. It commands the sea route connecting the Black Sea and the Mediterranean. The city's site has been of great commercial and military significance for centuries.

Istanbul has highly variable weather, with chilly to cold winters and warm to hot summers. Precipitation, including snow, is about 30 inches (760 mm) a year and falls mostly during winter.