In 2020 Istanbul was the largest city in Europe with an estimated urban agglomeration of 15.9 million people. The Russian capital, Moscow was the second largest city in 2020 at 12.5 million, followed by the capitals of France and the United Kingdom, with Paris at 11 million and London at 9.3 million people. Although both Russia and Turkey have most of their territory in Asia, Istanbul and Moscow are located within Europe, with Istanbul famously straddling both continents.

Source: Statista