It’s official: architects are in love with bamboo. A tree-hugging designer’s dream, bamboo is an eco-friendly, versatile, and durable material. More importantly, bamboo is the fastest growing perennial on the planet, making it symbolically a perfect choice for a city like Madrid, with its ever growing population and, subsequently, its enormous need for public housing. Located in the Carabanchel district, a “regeneration area” on the outskirts of Madrid, Carabanchel Social Housing is a state-subsidized, five-story residential project with 100 units, covered with bamboo louvres. (The structure itself is not made of bamboo, but bamboo is very prominent in the primary architectural statement it makes, due to the louvers.) Foreign Office Architects (FOA) credit Farshid Moussavi, Alejandro Zaera Polo, and others at FOA for Carabanchel Social Housing’s innovative design, which merges an environmentally conscious model with the social urbanization needs of the 21st century. One of the largest social housing projects in Europe, it was completed in late 2007.