Walden 7 is an apartment building designed by Ricardo Bofill Taller de Arquitectura and located in Sant Just Desvern near Barcelona, in Catalonia, Spain. It was built in 1975.^[1]

The name of the building is inspired by B. F. Skinner's novel, Walden Two, which depicts a utopian community and itself is a reference to Henry David Thoreau's novel Walden.^[1] It is noted for its use of modules to create apartments and many public community spaces.^[2]

The original project includes 446 residences. With a budget lower than the norm for subsidized housing at the time, Walden 7 was built in the area to the west of Barcelona. It was originally designed as one of five similar blocks.^[1] The building is composed of 18 towers which are displaced from their base, forming a curve and coming into contact with the neighbouring towers, described as a "vertical labyrinth with seven interconnecting interior courtyards."^[3] The area originally devoted to communal uses was reduced to allow an increased number of apartments. These apartments are formed on the basis of one or more 28-square-metre (33 sq yd) modules,^[1] which creates, on different levels, dwellings that range from single-module studios to large multiple-module apartments. Partitions between modules may be modified, designed to shift as family structures shift.^[1]

Walden 7 was designed with small, uniform windows and no central heating. Its original design included a bath in the middle of the room, which most residents removed. The original exterior façade was covered with small, red ceramic tiles backed with the wrong adhesive, creating a pedestrian hazard as the tiles fell off the building.,^[1][3] The local government began repairing the structure in the 1990s,^[1] and a 1995 refurbishment removed most of the tiles and replaced them with red paint.^[3] The only remaining tiles exist on the small balconies.^[1] The interior is painted in blue, purple, and yellow.^[2] It is accessible by tram; the stop near the building is called Walden.^[4]

Although the building is a private apartment complex, it offers public tours.^[4]

Walden 7 became instantly iconic and made the cover of the prestigious Architectural Design magazine in July 1975.^[5]

In an article for Architectural Digest, architectural historian Vincent Scully described Walden 7 as "a wildly expressionistic apartment house, part Gaudí, part Archigram."^[6]

In the 1993 film The Bilingual Lover, two characters live in Walden 7. The falling tiles are mentioned.^[7]

• Unité d'habitation
• La Muralla Roja
• Les Espaces d'Abraxas
• Antigone, Montpellier
• List of works by Ricardo Bofill Taller de Arquitectura