As city dwellers feel the squeeze on their living space and recreational areas, the twin residential towers in Milan, Italy offer up a refreshing vision of how urban skylines might look in the future.

Designed by Stefano Boeri architects, the towers, which rise to heights of 116 and 76 meters, contain more than 800 trees and 14,000 plants housed on steel-reinforced balconies.

The project was conceived as an alternative to urban sprawl, a phenomena prevalent in cities around the world which not only compromises communal green space but can also negatively impact the health and safety of citizens, according to research published in 2014 by Smart Growth America.

"Biodiversity is one of the most important challenges in our urban environment," Stefano Boeri says.

"The Bosco Verticale hosts more than 100 species of trees and plants but it also has started to host 20 different species of birds."

Along with being festooned with flora and fauna, the development has been decorated with awards, winning two prestigious architectural prizes including the 2015 Best Tall Building Worldwide, chosen by the U.S.-based Council on Tall Buildings and Urban Habitat.

Boeri and his team have their sights set on Switzerland next -- the Milan-based architects recently won a competition to erect a similar skyscraper in Lausanne -- the 36-story La Tour des Cedres takes its name from the cedar trees that will adorn the 117-meter high tower.

Switzerland has been a leader in incorporating ecological aspects to its urban infrastructure since the 1970s with an emphasis on green roofs where vegetation is planted helping foster habitats for wildlife.

The city of Basel boasts the largest area of green roofs per capita anywhere in the world and similar schemes have taken root across the continent.

In Stuttgart, around a quarter of all flat roofs are green while in London 1.3 million square-feet of roofs have green coverage, according to livingroofs.org.

"This a trend that's going on across Europe," says Jonatan Malmberg from the Scandinavian Green Roof Institute and manager of the Augustenborg Botanical Roof Garden — the world's first botanical roof garden in Malmo, Sweden.

By Matthew Knight, CNN