Casa Batllo

The locals call it the "House of Bones," and once you see it, you'll understand why. The balconies look like skulls, the columns resemble tibias, and the entire facade ripples as if the building is breathing. In 1904, textile industrialist Josep Batllo hired Gaudi to demolish his unremarkable apartment block and start fresh. Gaudi talked him out of demolition and instead performed what might be the most spectacular renovation in architectural history, finishing in 1906.

The most widely accepted interpretation is that the whole building is a three-dimensional tribute to Catalonia's patron saint, Sant Jordi, and his battle with the dragon. The roof, covered in iridescent ceramic scales, represents the dragon's back. The tower topped with a cross is Sant Jordi's lance, plunged into the beast. The facade's bone-like columns are the dragon's victims. It's a fairy tale told entirely through architecture.

Casa Batllo sits on the Passeig de Gracia in a stretch known as the "Block of Discord" — a row of buildings by four different Modernista architects all competing for attention. Gaudi's neighbors include Domenech i Montaner's Casa Lleo Morera and Puig i Cadafalch's Casa Amatller. The name isn't about conflict — "discordia" references the mythological apple of discord, because deciding which building is most beautiful is an impossible judgment.

The building was listed in Barcelona's Heritage Catalogue in 1962, declared a Historic and Artistic Monument in 1969, and became a UNESCO World Heritage Site in 2005. After hosting various businesses and residents for decades, the Bernat family opened the house to the public in 1995. It now welcomes roughly one million visitors per year.