Next door to Casa Amatller, Casa Batlló was designed by Gaudí in 1905. The facade’s sinuous curves in iron and stone give the structure a very lush appeal and the balconies, like those at La Pedrera, seem to be sculpted ocean waves. Floral references in the ornament turn more fauna-like as the building rises. The roof evokes the scaly skin of a dragon. Touring means climbing the spiral staircase around the central light shaft and starting with the Batlló family quarters, where Gaudí’s architectural flourishes and his furniture designs vie for your attention. Sr. Batlló’s office has a little nook with two benches and a stove for warmth—perfect for a courting couple to sit on one side and their chaperone on the other. Even this smallest of the rooms has a skylight to let in some natural light. The living room overlooks Passeig de Gràcia. All the decor, including the eddies of water in the swirling ceiling, allude to the marine world. The sewing room, which overlooks an interior courtyard, has an ingenious ventilation system of sliding slats that seem inspired by fish gills. The roof terrace has chimneys designed to evoke the backbone of the dragon slain by Sant Jordi (St. George), patron saint of Catalunya. The outdoor terrace has live music with cocktails from late June through September. An audiotour is included with admission, which has the effect of creating bottlenecks at each spot the tour highlights. Lines for admission can get quite long here; buy your ticket online in advance.