The Green Citadel of Magdeburg, a multifunctional residential and commercial building, was created by Friedensreich Hundertwasser and completed in 2005. It is the last completely designed and realised building that Friedensreich Hundertwasser worked on until shortly before he died on February 19th, 2000. Every window has its own individual shape. The roof is covered with grass - this is how the building received ist name. There is a numerous amount of trees: some of them on the roof, others on the walls outside the building. Residents of the building take care of the so-called “tree tenants”. After completion in 2005 the external condition of the building is no subject to change anymore. The growing trees and the fading house paint eventually may change the look of the building and are supposed to bring up the idea of ageing.