Verdict: first-timers should pick Casa Batlló (colorful, immersive); architecture lovers should choose Casa Milà (La Pedrera) for its sculptural rooftop chimneys. • Casa Batlló: inspired by the legend of Sant Jordi, with a wavy facade, mosaic tiles and sea-blue interiors, plus an immersive audio guide; general tickets from €29, morning €45, night €39, Magical Nights €59. • Casa Milà: wavy stone facade, warrior-like rooftop chimneys and the 'whale attic', focused on Gaudí's structure and engineering; Essential from €25, Premium €120, night/sunrise €39 — use code PEDRERASUMMER5 for 5% off. • Both sit on Passeig de Gràcia (Batlló at no. 43, Milà at no. 92), just a 5–7 minute walk apart; allow 1–2 hours each, so you can visit both in one day.