Barcelona contains some of the best-preserved medieval structures in Europe, as well as a wealth of imaginative contemporary buildings. The Passeig de Gràcia is lined with ritzy boutiques and fanciful modernist architecture. Nearby, Park Güell is an enchanting space created by Antoni Gaudí, the eccentric genius behind the extraordinary Sagrada Família (Church of the Holy Family) in the Eixample district, the undulating Casa Milà apartment building (also known as La Pedrera) and the colorful Casa Batlló (book the FastPass). La Rambla is an exuberant tree-lined promenade dotted with animated outdoor cafés, tapas bars and flower stalls. The high season can be insufferably crowded nowadays, especially when huge cruise ships fill the harbor.