If you intend to travel outside of the euro zone, you have to exchange your euros at your bank or an exchange office. Be careful, there are two rates: the sell rate, the rate at which foreign currency is sold in exchange for local currency, and the buy rate, the rate at which foreign currency is bought back from travellers to exchange into local currency. For example, if you intend to head to the United States, you will exchange your euros for U.S. dollars at the sell rate. And when you will return from the United States with your U.S. dollars, you will exchange your U.S. dollars back into euros at the buy rate. Of course, in the United States, you will do the opposite. As euro is not the local currency in the United States, you will buy dollars at the buy rate and sell dollars at the sell rate.