Casa Batlló - arches on the top floor :: Catenary arches on the top floor of Casa Batlló - a building designed by Gaudí in the Eixample district of Barcelona, Spain. . . The local name for the building is Casa dels ossos (House of Bones), and indeed it does have a visceral, skeletal organic quality. It was originally designed for a middle-class family and situated in a prosperous district of Barcelona.