Palau de la Musica Catalana, Barcelona Catalonia, Spain, (Palace of Catalan Music) is a concert hall designed in the Catalan modernista style by the architect Lluís Domènech i Montaner. It was built between 1905 and and is a UNESCO World Heritage Site.
Casa Batllo (World Heritage Site) - One of 2 houses by Gaudí in Barcelona that can be toured. truly amazing and worth the visit. go in the mornings, before the site gets crowded with architecture students.
SPAIN - The Benedictine monastery of Santa Maria de Monserrat is built into the mountain and offers visitors a staggering view. Monserrat is translated 'sawed mountain'. It is about 45 km northwest of Barcelona.