Since the success of New York’s High Line, converting an abandoned railway or highway into a public park has become a popular tool for any mayor hoping to make urban living a greener, healthier experience. In Seoul, mayor Park Won Soon believes it will transform the city’s entire downtown area.

A 1km overpass in the central Jung-gu district has been transformed into an elevated walkway and renamed Seoullo 7017 (a portmanteau of the city and the South Korean word for road). The pedestrian path has more than 24,000 trees and plants, performance areas, cafés and even trampolines above Seoul Station, a central hub for the city’s extensive underground network.

Built in 1970, the overpass had been slated for demolition but Park is pushing a “new urbanisation” agenda for Seoul that promotes restructure and renewal over demolition and construction. “Seoullo represents a shift towards giving the city back to citizens,” says Park. “I will make downtown Seoul pedestrian-friendly so that you can walk anywhere within 20 minutes.” He has not hidden his inspiration: indeed, he originally declared his intentions for the walkway while standing on the High Line itself.

Dutch practice mvrdv provided the design and project leader Kyosuk Lee believes that they won the competition because their entry was the only one that met the mayor’s brief: to reconnect the downtown area for pedestrians. Discussions are now underway to extend the number of “branches” that link the walkway to surrounding streets, an adjacent hotel and an office tower.

One issue still to be resolved is how to encourage people to walk from one end to the other. “The problem is that there are no popular destinations in the west,” says Joon Oh, the designer of the Seoul 7017 branding, who lives and works on the opposite side of Jung-gu to the shopping malls and office towers around Seoul Station.

Joon is taking matters into his own hands, suggesting a revitalisation of Sohn Kee Chung Park. The underused space honours South Korea’s first Olympic medallist, a marathon winner in 1936, so Joon plans to squeeze in an irregularly shaped 400-metre track.

With air traffic rising, the Polish government plans to replace Warsaw’s Chopin Airport with a larger Central Airport further from the capital. It would aspire to become a regional hub within central and eastern Europe for travellers flying between east and west. For now it sounds like an expensive pet project for the ruling Law and Justice party – and a hassle to get to for frequent fliers in and out of Warsaw.

Canada’s largest ferry operator, BC Ferries, is to revitalise its fleet this year with the addition of three new Polish-made ships. Since 1960, BC Ferries has been crucial to connecting Victoria and Vancouver. “It’s essential,” says David Obee, editor in chief of the Victoria Times-Colonist newspaper. “Victoria and Vancouver Island depend on ferries to get to the mainland. When they’re out of action we’re in trouble.”