The European Union explained
According to the EU website, the organization formed after the end of World War II with the goal of creating economic cooperation, which it was thought would make another continental war less likely. The organization was initially called the European Economic Community.
Currently, there are 28 member EU countries. Despite the June 23 vote to leave the EU, Great Britain is still a part of it until it goes through the withdrawal process.
In 1993, the EEC changed its name to the European Union. In 1999, the euro common currency was created for member countries. Great Britain never joined with the euro, but 19 of the 28 member countries do use it. At first the euro was virtual currency, but in 2002, banknotes and coins were issued.