Bosco Verticale

A decade on, it remains one of the genuinely compelling architectural stories of recent years: an ambitious idea, some extraordinary engineering, real environmental benefits, and an honest set of limitations that its own architect was first to acknowledge.

What it is

Bosco Verticale is a pair of residential towers — 19 and 27 stories, standing 80 and 112 meters tall respectively — built as part of the broader redevelopment of a former industrial area in Milan. Between them, they contain 111 luxury apartments. In terms of footprint and function, they are conventional enough. What makes them singular is the vegetation: 800 trees, 4,500 shrubs, and 20,000 plants from around 100 different species, distributed across the façades according to sun exposure. Evergreens face the southwest; deciduous trees face the northeast.

The numbers reward a moment’s attention. Spread out on flat land, that vegetation would amount to roughly 20,000 square meters of forest. Bosco Verticale contains it in a footprint of approximately 1,000 square meters — fifty times less. The towers don’t just host the forest; they concentrate it.

The engineering behind it

This is where things get genuinely fascinating. The steel-reinforced concrete balconies are 28 centimeters thick and protrude 3.35 meters from the building’s core, placed asymmetrically between floors specifically to allow tree canopies room to grow upward across multiple levels. Wind-tunnel testing was conducted to verify the trees could survive urban gusts without toppling. Botanists and horticulturalists were consulted throughout the design process to ensure the structure could bear the load — because trees on the 20th floor in a steel planter, roots and soil and all, are not a trivial engineering consideration.

The trees were pre-grown for two years, then craned into position during construction. No two balconies are identical. The asymmetry is structural as much as aesthetic — each terrace is sized to the plant it carries.

The architect’s vision

Architect Stefano Boeri described the project as “a home for trees that also houses humans and birds” — a framing that deliberately shifts priority away from human needs toward the relationships between humans and the rest of the living world. It’s an unusual way for an architect to describe a luxury apartment complex, and it signals something sincere about the project’s intent.

Boeri was so convinced of the concept’s broader value that he never registered copyright on the designs. His reasoning was direct: if the completed building proved the idea worked, he wanted other architects in other cities to replicate it without obstacle. It was, in effect, open-source architecture in service of a larger urban vision.

What it actually does environmentally

The environmental case is real, if specific. The 20,000 plants and trees convert approximately 44,000 pounds of carbon annually. The biodiversity hosted across more than 90 species has attracted new bird and insect populations to the district — urban wildlife that would have had little reason to be there before. The vegetation moderates interior temperatures across seasons, shading apartments from summer sun and buffering them from winter winds, reducing the energy load on climate systems. It also provides meaningful insulation from street-level noise and dust.

These are genuine, measurable benefits — and they matter more in a dense urban context, where green space is scarce and the heat-island effect is acute, than they would in a setting with abundant land.

Awards and influence

The International Highrise Award came in 2014, the same year the towers opened. The Council on Tall Buildings and Urban Habitat named it the world’s best tall building in 2015. Critics who predicted it would reshape skyscraper design were right: tree-covered residential towers have since been built in Shanghai, Lausanne, Eindhoven, Utrecht, Nanjing, and Athens, among other cities. The aesthetic vocabulary Bosco Verticale established — the living façade, the inhabited canopy — has become one of the defining visual languages of 21st-century urban architecture.

How to see it — and how to get there

Bosco Verticale is a private residential building, so the interior is not open to visitors. You won’t be getting past the lobby — but you don’t need to. The towers are striking enough from street level that simply walking around the exterior is a worthwhile experience, and the surrounding neighborhood makes it easy to spend a couple of hours in the area.

The best vantage points are from Piazza Gae Aulenti, the pedestrianized plaza just to the south, and from the Biblioteca degli Alberi — the Library of Trees — a public botanical park that sits at the base of the towers and extends the project’s green ethos down to ground level. The park is free to enter, beautifully landscaped, and one of the more pleasant spots in modern Milan for a slow walk. Taken together, the towers and the park feel like a single project: the forest in the sky meeting the forest on the ground.

For photographs, morning light hits the southwest façade well, and the towers are tall enough that you’ll want to step back — the park gives you the distance to take in the full height of both buildings at once.

Getting there: The Porta Nuova district is straightforward to reach from central Milan by metro:

• Line 2 (Green): Gioia station — about a 5-minute walk
• Line 5 (Lilac): Isola station — about a 7-minute walk
• Line 2 (Green): Porta Garibaldi station — about a 10-minute walk, passing through the broader Porta Nuova redevelopment zone, which is worth seeing as a whole

Tram line 2 also stops nearby if you’re coming from the city center. The area is well-connected and easy to combine with a visit to the Brera design district, which is a short walk or taxi ride away.

There’s no admission fee, no booking required, and no best time of year — though the deciduous trees on the northeast façade mean the building looks noticeably different in winter than in summer, which is itself an interesting thing to observe.

An honest caveat — from the architect himself

Bosco Verticale has attracted a consistent line of criticism since its opening, and it’s worth taking seriously. The primary objection is that it is, at its core, a luxury residential development: the environmental benefits are real but modest relative to simply planting an equivalent forest at ground level, and the “green architecture” movement it helped inspire has, in a number of subsequent projects, produced buildings that, according to critics, may be more photogenic than they are ecologically meaningful.

Boeri has not deflected this critique. He has described the towers explicitly as a prototype — a proof of concept, not a complete answer — and has since written an Urban Forestry Manifesto calling for systemic change in how cities incorporate nature: not just individual prestige buildings, but forests woven into urban planning at scale.

That honesty is, in its own way, part of what makes Bosco Verticale worth writing about. It is a building that its own creator refuses to oversell — which, in the world of architectural sustainability claims, is rarer than it should be.  It’s still worth a visit if you’re visiting Milan.