The name is a pun on the Spanish word manzana, which means both city block and apple, alluding to the three-way architectural counterpoint on this block and to the classical myth of the Apple of Discord (which played a part in that legendary tale about the Judgment of Paris). The houses here are spectacular and encompass three monuments of Modernisme -- Casa Lleó Morera, Casa Amatller, and Casa Batlló. Of the three competing buildings (four if you count Sagnier i Villavecchia's comparatively tame 1910 Casa Mulleras at No. 37), Casa Batlló is clearly the star attraction and the only one of the three offering visits to the interior.

The ornate Casa Lleó Morera (No. 35) was extensively rebuilt (1902-06) by Palau de la Música Catalana architect Domènech i Montaner and is a treasure house of Catalan Modernisme. The facade is covered with ornamentation and sculptures depicting female figures using the modern inventions of the age: the telephone, the telegraph, the photographic camera, and the Victrola. The inside is even more astounding, another anthology of Art Nouveau techniques assembled by the same team of glaziers, sculptors, and mosaicists Domènech i Montaner directed in the construction of the Palau de la Música Catalana. The Eusebi Arnau sculptures around the top of the walls on the main floor are based on the Catalan lullaby "La Dida de l'Infant del Rei" ("The Nurse of the King's Baby"), while the stained-glass scenes in the old dining room of Lleó Morera family picnics resemble Moderniste versions of impressionist paintings. The house is closed to the public, but call to check about visits.

The neo-Gothic, pseudo-Flemish Casa Amatller (No. 41) was built by Josep Puig i Cadafalch in 1900, when the architect was 33 years old. Eighteen years younger than Domènech i Montaner and 15 years younger than Gaudí, Puig i Cadafalch was one of the leading statesmen of his generation, mayor of Barcelona and, in 1917, president of Catalonia's first home-rule government since 1714, the Mancomunitat de Catalunya. Puig i Cadafalch's architectural historicism sought to recover Catalonia's proud past, in combination with eclectic elements from Flemish or Netherlandish architectural motifs. The Eusebi Arnau sculptures range from St. George and the dragon to the figures of a handless drummer with his dancing bear. The flowing-haired "Princesa" is thought to be Amatller's daughter, while the animals up above are pouring chocolate, a reference to the source of the Amatller family fortune. Casa Amatller is closed to the public (call or ask about any change in this situation), but a boutique and small gallery inside the entryway sells Art Nouveau objects and organizes exhibits related to Modernisme.

Gaudí at his most spectacular, the colorful and bizarre Casa Batlló (No. 43), with its mottled facade resembling anything from an abstract pointillist painting to a rainbow of colored sprinkles on an ice-cream cone, is usually easily identifiable by the crowd of tourists snapping photographs on the sidewalk. Nationalist symbolism is at work here: the scaly roof line represents the Dragon of Evil impaled on St. George's cross, and the skulls and bones on the balconies are the dragon's victims. These motifs are allusions to Catalonia's Middle Ages, its codes of chivalry, and religious fervor. Gaudí is said to have directed the chromatic composition of the facade from the middle of Passeig de Gràcia, calling instructions to workmen on scaffolding equipped with baskets of multicolored fragments of ceramic tiling. The interior design follows a gently swirling maritime motif in stark contrast to the terrestrial strife represented on the facade. Passeig de Gràcia 43, between Consell de Cent and Aragó, Eixample. 93/216-0306. www.casabatllo.es. EUR 17. Daily 9-8. Passeig de Gràcia.