Moscow is undergoing its biggest reconstruction effort since the 1980 Olympics. The $2bn (€1.9bn) My Street project is designed to “make the capital’s streets more pedestrian-friendly by 2018”, says Denis Boikov, executive director of the Moscow Urban Forum.

Mayor Sergei Sobyanin won a second term in 2013 by pledging to improve the quality of life in the wealthy but notoriously congested city; he launched the project in 2015. So far more than 50 streets have been refurbished: electric wires and advertising boards have disappeared, roads have been pedestrianised and 2,000-plus summer terraces have opened.

“Sobyanin is the big hope,” says Grigory Revzin, a professor at the Vysokovsky Graduate School of Urbanism. “He is reconstructing the uncomfortable city built by Soviet authorities and so far the outcome is positive.”

Most of Serbia’s metal-and-concrete playgrounds are Yugoslav-era relics that look like death traps and are deserted. Enter the Creative Playgrounds project. Originally a Belgrade Design Week initiative, it worked to transform two play areas in the capital’s Kalemegdan Park. Serbian architects used Finnish equipment to make landscaped, immersive and safe spaces.

Children can now scramble over wood-and-rope climbing frames and chase each other across bouncy bridges. The newly revitalised playgrounds are packed and more are on the way, with one set to open in the city of Kragujevac in February.

For decades the concrete-lined Los Angeles River has been a blot on the city but in recent years, sections of it have been spruced up with bike paths and ecological restoration. And one stretch, not far from downtown, has lent itself to particularly unexpected uses, fostering both creativity and community.

The Bowtie is a seven-hectare patch shaped like the accessory after which it’s named; formerly a Union Pacific rail yard, it juxtaposes decaying industry with resurgent nature. California State Parks bought the site in 2003 and later decided to collaborate with Clockshop, an LA arts organisation. “We wanted to imagine state park land in a different way,” says Sean Woods, superintendent of the Los Angeles Sector of California State Parks.

One goal, Woods says, is to “allow this space to function as a canvas”. Since 2014 artists have completed public works that encourage people to interact with the site. Architecture students designed and built temporary structures, such as benches made of wood and reclaimed metal. Another project involved signs along the river with information about the Bowtie.

A second goal is to engage the community. Campouts, which include activities such as birdwalks and campfire storytelling, have been especially popular. When the most recent event was held in May, more than 200 people attended, with even more on a waiting list; organisers give priority to first-time campers and children from nearby neighbourhoods. “We’re trying to push conversations about what it means to be an Angeleno,” says Clockshop’s Savannah Wood.

In an effort to fight climate change, the city of Santa Monica requires that as of this year, all newly built single-family homes must be zero-net energy (ZNE): they must produce more power than they consume.