Everyone knows that deck and patio space comes at a premium in the city – particularly lush rooftop garden areas, such as the uncanny overgrown green roof in New York City shown in the image above. Though some of the best such green urban spaces are cut off to most of us, other great designs are only semi-private or entirely public.

The above photographic examples (part of a collection from Oobject) are all more-or-less accessible to the public, from the extensive wrap-around roof garden paths of the Waldspirale (literally: ‘Forest Spiral’) apartment complex in Germany to the green roof of the convention center visible from anywhere in Vancouver, Canada and waterfront sculpture park in Seattle open during museum hours.

Here’s some more info about that Waldspirale building, via Wikipedia: “The Waldspirale is a residential building complex in Darmstadt, Germany, built in the 1990s. The name translates into English as forest spiral, reflecting both the general plan of the building and the fact that it has a green roof. It was designed by Austrian artist Friedensreich Hundertwasser, planned and implemented by architect Heinz M. Springmann, and constructed by the Bauverein Darmstadt company. The building was completed in 2000.”

Other green roofs are like urban backyards in the only available space – on top of an existing building. A relatively intensive (meaning: one meant to support the weight of heavy plants or even trees) green roof such as the one in the photo above usually involves a structural retrofit to support it. It is not cheap but the results can be beautiful.

More conventional public and private green rooftop deck designs attached to hotels and other downtown structures tend to be well-organized and heavily manicured, a kind of idealized oasis above the pulsing urban flow on the streets below. As more and more people think about the sustainable benefits of eco-friendly roofs, however, this more formal expression is increasingly becoming a thing of the past.