They called it "vertical forests": two towers in the heart of Milan (120 and 80 m) covered in a huge number of trees and shrubs (700 trees and 20,000 other plants) in 8,900 square meters of terraces, in an effort to reduce inner city smog without sacrificing valuable real estate. The design, by Italian architect Stefano Boeri is known as Bosco Verticale (Vertical Forest), and will be erected in Milan as part of efforts to improve the air quality in one of Europe’s most polluted city. (In 2003 a medical study found that living in Milan and breathing its air was almost the equivalent to smoking a packet of cigarettes a day.)

The project was approved a few years ago, and construction is now entering the final stages, with a completion date expected for later in the year.

The hopes are that the trees and plant life will help to consume CO2 and produce oxygen, reducing the dangerous levels of smog in the city and clearing the air. They will also provide new habitats for insects and birds, provide shade in the summer (which will reduce energy bills for air conditioning), and provide protection from storms.

When completed the two towers will provide the equivalent of more than 107,000 square feet of natural forest and 538,000 square feet of living space.