The project for “The city in space” was eventually able to take shape on a suburban plot formerly occupied by a cement factory. Working to a budget appreciably lower than the norm for subsidized housing at the time, with unusual funding, Walden-7 rose up as a monument and point of reference in this area to the west of Barcelona. The building is composed of 18 towers which are displaced from their base, forming a curve and coming into contact with the neighbouring towers. The result is a vertical labyrinth with seven interconnecting interior courtyards, as far removed as possible from the model of the uniform, repetitive housing block. The considerable area originally devoted to communal uses was reduced to allow an increased number of apartments. The apartments are formed on the basis of one or more 30 sqm square modules creating, on different levels, dwellings that range from a studio consisting of a single module to a large, four-module apartment. The program includes 446 dwellings, public spaces, meeting rooms, bars and shops on ground floor, and two swimming pools on the flat roof.