Barcelona, the capital of the Catalunya, is a major economic centre, with one of Europe's principal Mediterranean ports, and its airport is the second largest in Spain. Founded as a Roman city, Barcelona became the capital of the Counts of Barcelona and the Crown of Aragon. Besieged several times during its history, Barcelona is today an important cultural centre and a major tourist destination and has a rich cultural heritage. Particularly renowned are architectural works of Antoni Gaudí and Lluís Domènech i Montaner that have been designated UNESCO World Heritage Sites.