Istanbul

As Turkey's biggest city, Istanbul is the country's economic and cultural epicentre, as well as its historic hub. Turkey's largest city, Istanbul, spans the Bosphorus strait and is located in both Europe and Asia. The city has a population of more than 15 million people, accounting for 19 percent of the country's total population. Istanbul is the most populated metropolis in Europe and the fifteenth-largest city in the world, according to the United Nations.

Constantinople (Constantinopolis) was founded as Byzantion by Megarian colonists in 657 BCE, and changed its name by Constantine the Great first as New Rome (Nova Roma) in 330 CE during the official dedication of the city as the new Roman capital, which he changed to Constantinople (Constantinopolis) shortly afterwards. The city expanded in size and influence, becoming a beacon of the Silk Road and one of the most important cities in history. From 330 to 1204, it served as the imperial capital of the Roman/Byzantine (330–1204), Latin (1204–1261), Byzantine (1261–1453), and Ottoman (1453–1922) empires, a period of over sixteen centuries. The city had a significant role in the growth of Christianity throughout the Roman and Byzantine periods, until being transformed into an Islamic bastion after the Fall of Constantinople in 1453 CE. Following the Turkish War of Independence, Ankara was designated as the capital of the newly established Republic of Turkey in 1923, displacing Istanbul as the country's capital. The name of the city was formally changed to Istanbul in 1930, replacing the name of the city that Greek speakers had been using since the eleventh century to refer to the city colloquially.

In 2018, more than 13.4 million international tourists arrived to Istanbul, making it the world's fifth most popular tourist destination, eight years after it was designated as the European Capital of Culture by the European Union. There are many World Heritage Sites in Istanbul, and the city is also home to the headquarters of major Turkish corporations, which together make for more than thirty percent of the country's GDP.