Built in 1889 for the Reverend Mothers of St. Theresa, when Gaudí was in a relatively benign creative fervor and still occasionally using straight lines, this building, still a school, showcases upper floors reminiscent of those in Berenguer's apartment house at Carrer de l'Or 44 with its steep peaks and verticality. Hired to finish a job begun by another architect, Gaudí found his freedom of movement somewhat limited in this project, both in budget and in the work completed before he started. The dominant theme here is the architect's use of steep, narrow catenary arches and Mudejar exposed-brick pillars. The most striking effects are on the second floor, where two rows of a dozen catenary arches run the width of the building, each of them unique because, as Gaudí explained, nothing in nature is identical. The brick columns are crowned with T-shape brick capitals (for St. Theresa). The tiny patios filled with plants are Gaudí's nod to the Moorish courtyard tradition. Look down at the marble doorstep for the inscription by mystic writer and poet Santa Teresa de Avila (1515-82), the much-quoted todo se pasa (all things pass), the letters themselves partly worn away by a century of footsteps. For visits, consult the Ruta del Modernisme (93/317-7652; 902/076621 within Spain. www.rutadelmodernisme.com).