Berlin is located in the northeast of Germany. It has existed since the 13th century. Berlin's population is around 3.6 million.
The European Union is a supranational (alliance/organization involving several countries, member states give up some of their power) economic and political union between 27 European member states. Member states of the European Union have open borders with each other and share a common currency, the euro. Germany is a founding member of the organization, which formed on January 1, 1958.
