The new fashion is to build cities in airports. And this new city will have seven neighborhoods and film production. It will take 30 years to complete
The interior of the abandoned airport that is being transformed into a 26 billion euro sustainable city
by Nell LewisCNN
EDITOR’S NOTE Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, along with the solutions. The initiative, from Rolex, has partnered with CNN to promote awareness and education around key sustainability issues and to inspire positive action.
Downsview Airport, northwest of Toronto, Canada, has undergone some transformations over its time. Around 100 years ago, the first airfield was built: a short runway and an industrial building between farmers’ fields. It was the headquarters of De Havilland Canada, a pioneering company in global aviation.
It became a warplane production center during World War II, and in the early 1990s the airfield was acquired by Bombardier, a Canadian aerospace manufacturer. In 2024 it was closed, due to the company moving its facilities.
But, at the beginning of 2026, construction will begin on what will be the biggest development of the site to date. The 150-hectare area is being transformed into an urban district housing more than 50,000 inhabitants and 30 hectares of green and open spaces. It will become “YZD” – a reference to the airport’s former code – a 30-year, 26 billion euro undertaking and one of the largest projects of its kind in North America.
The airstrip will be transformed into a public park images Northcrest Developments
The two-kilometer-long track, the centerpiece of the site, will become a pedestrian park connecting seven neighborhoods. Each will be distinct, with its own housing, libraries, shops, schools and community centers, but the runway will act as the “connecting fabric” – linking everything together, while “respecting and celebrating the aerospace legacy of the site,” says Derek Goring, executive director of Northcrest Developments, the company leading the project.
Derek Goring explains to CNN that maintaining the site’s history was a key part of Northcrest’s vision — and also a big plus. “One of the biggest challenges with large-scale urban renovations is that, when you have nothing to start with, they can appear generic,” he says. “We want to take advantage of what exists and make the most of it. This helps give character and makes everything more interesting and unique.”
A greener future
Preserving the history of the site is not just a sentimental decision, it is also a practical decision in terms of the environmental footprint.
“There is a lot of carbon embodied in existing buildings and, rather than demolishing them and building everything new, there is a huge benefit, in terms of carbon, in maintaining these buildings”, reveals Derek Goring.
The airport’s vast industrial hangars, built between the 1950s and 1990s, will be maintained and converted into commercial buildings, intended for film production, light industry and clean technology. Its roofs will be covered with grass and plants, which, according to the developer, will help absorb rainwater and reduce the risk of flooding, while increasing biodiversity in the urban center.
Although the track will not be maintained in its current form, the concrete and asphalt it is made of can be reused as aggregate for roads or pavements, says Derek Goring. Other Canadian airports and military bases were found to contain “forever chemicals” that could contaminate groundwater. Developers said that while a small portion of the YZD site “reflects its historic industrial and military past,” they have hired specialist environmental consultants who will “help us understand and mitigate any legacy conditions” and will continue to review the site in collaboration with local authorities.
Landscape architecture firm Michael van Valkenburgh Associates (MVVA) is tasked with creating a design concept for the track, having won an international competition for the design in October. Its goal is to bring nature back to space.
Emily Mueller De Celis, partner at MVVA, looks back to the site’s history before it was an airfield or farmland and when it was part of the Carolinian forest in southern Ontario. They aim to recreate native habitats and invite wildlife to return to the site.
“Nature on the existing site had to be suppressed to make it safe for aviation operations,” explains Derek Goring, which meant preventing nesting birds, despite its location along the Atlantic Flyway, a major migratory route.
The “renaturalization” of the site will also bring great benefits in terms of water management, reveals Derek Goring. YZD is located at the highest point in Toronto, between large watersheds. Through the project, the MVVA aims to find ways to absorb as much water as possible to reduce the risk of flooding downstream. This will be done through strategic planting and the use of bioswales (vegetated canals that collect, filter and absorb rainwater).
Environmental sustainability is part of the big picture at Northcrest. The huge undertaking will take three decades to complete, so it is necessary to think about the future and prepare for more extreme weather conditions and the potential effects of climate change, says Derek Goring.
Derek Goring adds that Northcrest has been working with Danish landscapers SLA – famous for their work on projects such as Copenhagen’s energy recovery plant, transformed into a skystrip – on the “City Nature” concept, which involves creating lots of green spaces in urban environments to improve quality of life.
The YZD site is already surrounded by a network of train and metro stations, so the project will utilize these and encourage their use and car-free alternatives. There will be wide cycle paths and a last kilometer bus system.
“It doesn’t mean there aren’t any cars – the track is the only area without cars”, highlights Derek Goring, “but we are trying to make walking and cycling the easiest, safest and most convenient.”
Legacy
The transformation of abandoned airfields into green parks and sustainable living areas has become a global trend, with examples such as Berlin’s Tempelhofer Feld and Athens’ Ellinikon Metropolitan Park.
The YZD is different, says Derek Goring. “The fact that our site is located in the geographic center of Canada’s largest metropolitan area, with existing public transportation infrastructure, means that this is more of a city-building exercise than a park-building exercise.”
Construction of the first neighborhood, the 40-hectare “Hangar District”, including 3,000 new homes, begins early next year – with completion scheduled for 2031. It will be the first phase of a 30-year transformation, with neighborhoods being built one by one and the track slowly evolving between them all.
One of the biggest challenges of the project is its scale and the time it will take to build. Goring says they don’t have 26 billion euros available and that’s why they intend to build in phases, making an investment, getting a return and reinvesting.
During such a long development period, expect current ideas and designs to evolve. The objective is not to be too prescriptive from the beginning: “The world is going to change a lot… We are not trying to decide in 2025 what the future should be in 20 or 30 years,” he says.
“Ultimately, it’s about providing a really high quality of life” and merging with the current city. “We want you to feel like you’re a part of Toronto.”
