An article on MSNBC about new security measures for visa-free travel into the US contains the following:

"There are currently 27 countries whose citizens are not required to obtain visas for U.S. entry, including those in most of western Europe as well as Andorra, Australia, Brunei, Japan, New Zealand and Singapore."

I had thought that Andorra's location in the Pyrenees between Spain and France would place it in Western Europe.