Antoni Gaudí never saw his Sagrada Família finished — the architect died in 1926 when only the Nativity façade and a single bell tower stood complete. Construction continues today under six successive chief architects, following plaster models and sparse drawings salvaged after anarchists torched Gaudí's workshop in 1936. The basilica's eighteen spires, once ridiculed as impossible, now rise above Barcelona's Eixample grid, their hyperboloid geometry computed by modern engineers using the catenary-chain models Gaudí hung from his studio ceiling. Barcelona Gaudi houses tickets open the architect's most radical domestic commissions. Casa Batlló, remodelled in 1906 for textile magnate Josep Batlló, eliminated load-bearing walls to flood interiors with light through blue-tinted skylights and a facade that undulates like wave-sculpted rock. La Pedrera, completed four years later, took the principle further — its self-supporting stone curtain walls allowed Gaudí to design floor plans with no fixed partitions, predicting open-plan modernism by half a century. Both buildings horrified conservative critics; one newspaper compared La Pedrera's rooftop chimneys to medieval executioners. Park Güell began as a garden city for Barcelona's bourgeoisie, modelled on English suburban estates. Eusebi Güell purchased fifteen hectares on Carmel Hill in 1900, and Gaudí transformed the scrubland into serpentine paths, viaducts, and the mosaic-clad plaza that now overlooks the city. Only two of sixty planned houses sold — the project bankrupted Güell — but the park's trencadís technique, assembling broken ceramic shards into flowing mosaics, became a signature of Catalan modernisme. The municipal government acquired the site in 1922 and opened it as a public park four years later. Today these structures anchor Barcelona's modernisme trail, drawing eight million annual visitors. Barcelona Gaudi houses tickets tours grant priority access to interiors closed to general admission — Casa Batlló's attic ribs, Park Güell's hypostyle hall with its eighty-six Doric columns, and Sagrada Família's Passion facade workshops where stone carvers still hand-finish each trumpet-angel and vine scroll. The UNESCO inscriptions came in 1984 and 2005, recognizing not preservation but living craft.