Le Lignon is an urban development in the town of Vernier, canton of Geneva, Switzerland. It consists of two large buildings and is one of the largest apartment complexes in the world, containing 2,780 units. It is located on former farmland and was built to address a housing shortage in the 1960s and early 70s. It houses over 6,000 residents and of floor space, including a school and a medical center. It makes up a significant portion of the population of Vernier, a town of only some 34,000 residents. With an area of , the population density rivals that of the island of Manhattan. In the 2010s, the building went through a thermal insulation retrofit to improve performance.