Barcelona's most famous neighborhood, this late-19th-century urban development is known for its dizzying unnumbered grid and dazzling Art Nouveau architecture. Named "Expansion" in Catalan, the district appears on the map as a checkerboard above Plaça de Catalunya. Shopping, art-gallery hopping, exploring Moderniste town houses, and sampling the city's finest cuisine is an ongoing pastime for visitors and barcelonins alike.

Somewhat wide, bright, and noisy, the Eixample (ay-shompla), is an open-air Moderniste museum. With its hard-line street grid the Eixample is oddly labyrinthine for a Cartesian network (the planners forgot to number it). Many Barcelona residents find it possible to get lost on these unnumbered and unalphabetized streets, maybe because it's so entertaining. Divided into the well-to-do Dreta to the right of Rambla Catalunya looking inland, and the more working-class Ezquerra to the left of Rambla Catalunya, Eixample locations are also either mar (sea side of the street) or muntanya (mountain side).

The Eixample was created when the Ciutat Vella's city walls fell in 1860, and Barcelona embarked upon a vast expansion fueled by the return of rich colonials from the Americas, aristocrats who had sold their country estates, and the city's industrial power. The street grid was the work of urban planner Ildefons Cerdà, and much of the building was done at the height of Modernisme by a who's who of Art Nouveau architects, starring Gaudí, Domènech i Montaner, and Puig i Cadafalch. In this architectural feast the main course is Gaudí's Sagrada Família church. The Eixample's principal thoroughfares are Rambla de Catalunya and Passeig de Gràcia, where the city's most elegant shops vie for space among its best Moderniste buildings.