【Hosptial de Sant Pau - Barcelona has not only Gaudí】 

Hospital de Sant Pau is a complex built in the early 18th century, consisting of 12 pavilions connected by long underground galleries and a large green space. It’s one of the most outstanding Art Nouveau style buildings in Barcelona, which has made it UNESCO World Heritage site since 1998.
Hospital de Sant Pau was a fully functioning hospital until June 2009, when the new hospital opened next to it. After 5 years of restoration, the complex reopened in 2014 as a museum and cultural center.