
SeoulLo 7017 SkyGarden, Seoul
A handful of subway lines converge beneath this disused overpass in central Seoul, so pulling it out of circulation didn’t create much congestion – unless you’re counting people. Handing over 1,000 sq m to Dutch architects MVRDV attracted pedestrians to a foreboding, traffic-clogged part of downtown. The lure? The opportunity to explore 24,000 plants – the largest variety of native species open to the Korean public. MVRDV organised the flora in ‘neighbourhoods’, or families, and planted in alphabetical order, like a botanical garden. Tea pavilions break up the 1km journey. Photography: Ossip van Duivenbode

The Bentway, Toronto
Toronto lost its views to Lake Ontario when the 13-metre-high Gardiner Expressway was built in 1958, slicing off the lakeshore. Recently, public bodies on both sides of the motorway worked together to hire urban designer Ken Greenberg and landscape architects Public Work to create a mile-long park under the cover of the road.
The Bentway incorporates outdoor seating, public art, an amphitheatre and a skate park, making the journey between city and lake far less ominous. Photography: Nic Lehoux

Projet Bonaventure, Montreal
The 1960s provided Montreal with unforgettable Brutalist architecture at the expense of massive tracts of wasteland. New roadworks swept suburbanites along the Lachine Canal into downtown past decaying postindustrial blight.
Landscape architect Luu Nguyen, together with urbanists Rousseau Lefebvre, reimagined a blustery junction with a series of islands supporting native plants, loungers, fitness equipment and playgrounds. A sculpture park headlined by Catalan artist Jaume Plensa draws pedestrians from the old town into Griffintown and Little Burgundy, now deep into gentrification. Photography: Marie-Eve Boisvert, Groupe Rousseau Lefebvre

The Tide, London
Despite being purpose built, the Tide winds upward nine metres to better take in artworks by Damien Hirst, Gary Hume and Antony Gormley along its one-kilometre stretch (a further 4k will be completed next year). It moves the neighbourhood’s centre of gravity away from the O2 centre and toward the Thames-side Jetty.
It’s no surprise architects Diller, Scofidio & Renfro riffed on the High Line when drafting The Tide, the new elevated walkway in North Greenwich (completed in collaboration with Neiheiser Argyros). They were, after all, co-designers of New York’s first linear park. Photography: Charles Emerson

Cheonggyecheon Park, Seoul
A serial offender in the annals of poor 20th-century planning, Seoul paved over its east-west Cheonggyecheon River, then built an elevated highway above, engineering a massive no-go zone.
Its rescue effort rewrote the rules. In the early-Aughts the city unearthed and landscaped 3.6 miles of waterway then diverted traffic and transformed the motorway into parkland. It’s now a safe haven for wildlife and, thanks to dedicated public transport, people.

BQP, New York
The Brooklyn-Queens Expressway (BQE) is one of the most divisive elevated freeways devised by ‘master builder’ Robert Moses in the midcentury. Among those who have weighed in on its revamp is Bjarke Ingels of BIG, with a scheme called BQP, an acronym that emphasises ‘parkland’ rather than ‘expressway’. Ingels proposes diverting traffic to a wide boulevard alongside Brooklyn’s East River, then landscaping overtop the old and new roads. Ten acres of parkland would blanket the new riverside road, and an additional linear park would follow the route of the former expressway. Images: Big Bjarke Ingels Group