With around 20 million tourists per year, Barcelona is on the popular side...But it's with good reason. It's a sophisticated beach-side party town with world class architecture. The fantastical Sagrada Família church and other modernist landmarks designed by Antoni Gaudí dot the city. Museu Picasso and Fundació Joan Miró feature modern art by their namesakes. City history museum MUHBA, includes several Roman archaeological sites.