Berlin is the most populous city in the European Union, as calculated by city-proper population (not metropolitan area).
The spike in population in 1920 is a result of the Greater Berlin Act.
Berlin has a large population of a migration background. On 31 December 2010 the largest groups by foreign nationality were citizens from Turkey (104,556), Poland (40,988), Serbia (19,230), Italy (15,842), Russia (15,332), United States (12,733), France (13,262), Vietnam (13,199), Croatia (10,104), Bosnia and Herzegovina (10,198), UK (10,191), Greece (9,301), Austria (9,246), Ukraine (8,324), Lebanon (7,078), Spain (7,670), Bulgaria (9,988), the People's Republic of China (5,632), Thailand (5,037). There is also a large Arabic community, mostly from Lebanon, Palestine and Iraq. Additionally, Berlin has one of the largest Vietnamese communities outside Vietnam, with about 83,000 people of Vietnamese origin.