the european union was formally established (with the maastricht treaty) on november 1, 1993. however, january 1,2002, is a day that many people remember. it wasn't just the start of another new year. it was also the start of anew era for the 304 million people living in 12 european countries. on that day, the euro became the official currency of their countries. the european union currently has 27 member states, and new members are expected to join. citizens of member countries can travel freely, live, study, and work in any of the member countries.