You may know that in Barcelona, as elsewhere in Europe, the date is written dd/mm instead of mm/dd as we do in the States. You may not know that 9/11 also has a different meaning in Barcelona. It is the national day of Catalonia, celebrated annually on September 11.
The History Channel has produced an excellent interactive video feature about America’s 9/11: http://www.history.com/content/9-11/102-minutes.
Great group of Catalonia’s 11/09 pictures on Flickr: