Brutalist architecture is commonly associated with a cold, austere aesthetic, but architects have long found ways of incorporating greenery into their designs, creating a striking contrast between hard concrete and the soft, organic shapes of plants. And if not designed, nature often has its own way of reclaiming the built environment. From green roofs to living walls, from the pocket gardens of Le Corbusier's Unite d'Habitation to the lush couryards and conservatory of London's Barbican Centre, Olivia Broome has curated an impressive selection of striking images from around the world.