Barcelona's medieval heart is picture-postcard perfect, and complemented by soaring avant-garde buildings from the world's greatest architects. There is no shortage of museums large and small, but what makes the city truly unique is Modernisme – the Catalan version of art nouveau. The best-known Modernista buildings – La Sagrada Família, Casa Batlló, La Pedrera – are by Antoni Gaudí, but his contemporaries' creations are every bit as stunning. Special mention goes to the glorious Palau de la Música Catalana and the Recinte Modernista de Sant Pau.