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.