This monumental building, built between 1902 and 1930, covers an area of more than 35 000m². It was created by Domènech i Montaner, helped by his son, thanks to the patron Pau Gill, whose initials are intertwined on the façades of the 16 buildings. Glazed ceramic mosaics adorn the pavilions, depicting mythological scenes and the history of Catalonia. Designated a World Heritage Site in 1997, then rehabilitated, the hospital now houses a research centre.