In Europe, the only place I have ever seen U.S. dollars is the LHR airport. I have never seen U.S. dollars accepted anywhere else in Europe. Since the introduction of the euro about 20 years ago, things have gotten simpler since a single currency is accepted in most European Union countries, there are still many countries (Iceland, Norway, Croatia, Denmark come to mind) who do not accept euros. In this blog post The Traveling Professor gives some simple and never published before ways to exchange currency to use in Europe.