When pressed on his fascination with trees, the architect Stefano Boeri is prone to nostalgia. ”When I was a kid, I used to quote a novel written by an Italian writer, Italo Calvino, called ‘The Baron in the Trees’. It was the story of a young duke who decided, when he was 12, to abandon his family and spend the rest of his life living on the branch of a forest.” This analogy might better explain the 64-year-old’s fascination with nature - a life-long fixation which led him to design the world’s first vertical forest.

Building a forest in the sky

Bosco Verticale - a pair of residential towers situated in the heart of the Porta Nuova district of Milan - is home to over 21,000 trees, shrubs and perennial plants. The vegetation converts an average of 44,000 pounds of carbon each year, while mitigating noise pollution from the street-level traffic below.