Day and night, visitors can descend an aluminum gangway behind the REI Co-op at North Kingsbury Street and West Eastman Street near Goose Island and find themselves seemingly walking on water, wandering across an almost imperceptibly rocking wooden boardwalk, surrounded by five-foot-high plants.This fall, the area of this string of small, human-made islands known as the Wild Mile, drew migrating white-throated sparrows, fall warblers and dark-eyed juncos to feast on the seeds of sedge, prairie clover and Joe-Pye weed. Tropical white and pink hibiscus blooms stood out among the fading greens and rusty browns of summer’s bounty, 60 native species in all.One of the wildest things about the Wild Mile is that it got built at all following a decade of experimentation and mad science by a group of young men, led by Nick Wesley, and their Urban Rivers organization. The nature-starved Chicago River has slowly and spectacularly attracted the public’s attention and redevelopment dollars over the past decade. Of the advancements that have driven its revitalization from open sewer to a desirable resource, its floating parks — the one at Goose Island was the first — are perhaps the boldest attempt to combine nature and advanced art and design to create a unique open space.Urban Rivers is building gardens in cities, a reversal of the 1830s Chicago motto Urbs in horto.Building floating islands mostly entails exhausting labor. But fueling this was Wesley’s naivete. When he and his ragtag bunch set out, they wanted to clean up and green up the walled-off, denuded and degraded waterway and maybe even grow a few vegetables. The Wild Mile in the Goose Island neighborhood is home to a plethora of native plants and wildlife.Manuel Martinez/WBEZ In his zeal, Wesley thought they could just gather a bunch of free pickle buckets from Whole Foods, rappel down the steel sheet pilings and float them in the river. He also presumed that getting a permit from the city of Chicago would take a couple of weeks. It took two years. He dreamed they could get someone at Chicago’s storied architecture firm Skidmore, Owings & Merrill to answer an unsolicited email. Decorated architect Philip Enquist did reply, giving the group much needed credibility.Wesley kept thinking that he and his merry band could just do stuff, permitted or not — until finally, one day in 2022, there it was: the Wild Mile. The manmade wetlands now sit on a bank of the river across from a garbage-transfer station. Their creation was recognized earlier this year with the Field Museum’s global award for environmental conservation.“It’s incredibly unique,” says Enquist, whose own award-winning work has centered on urban planning. “The design is exceptional. This project is a great example of addressing resilience and nature in a new and different way. It was just a phenomenal innovative breakthrough.” The parks in the Wild Mile are perhaps the boldest attempt to combine nature, and advanced art and design, to create a unique new open space.Manuel Martinez/WBEZ An urban oasisOn different days this fall, you could find people practicing yoga on the Wild Mile’s group activity platform and students from the Latin School sketching plants in notebooks and launching kayaks from the handicap-accessible dock.Mostly, people walked quietly on the winding pathways, sat down to read or just looked out at the scenery. Wesley, 34, grew up in La Grange, with Salt Creek and neighboring woods his stomping ground. He got an early lesson in hydrology when the raft he built with 50-gallon drums flipped over during one ill-fated adventure. What he learned from that came in handy later, when calculating the correct balance of flotation and ballast for his “next-gen” rafts, the pontoon-based river platform.He comes from a family of designers and engineers. His mother Eva Stevens was a fashion designer who says she missed her true calling as an architect. She designed sweaters for the I.B. Diffusion brand.  Wesley got a college degree in entrepreneurship, and spent much of his spare time experimenting with growing food more sustainably through various forms of hydroponics.Manuel Martinez/WBEZ As a kid, Wesley spent time running around the Berwyn shop floor of Labelette, the family’s label machine company, founded by one of his grandfathers.Stevens describes her son as a reader, listener and information junkie.“He has always been a kid to not follow what everyone else does,” she says. “He’s always a step ahead of the rest of the world.”Wesley got a college degree in entrepreneurship and spent much of his spare time experimenting with vertical farming, growing food more sustainably through hydroponics. He did an internship at Plant Chicago, a mushroom-growing startup in Berwyn. In the city, he and a couple of his friends grew kale and other vegetables on the river using floating pickle buckets. The plants grew well but weren’t edible due to lead contamination.“We didn’t know what we were doing,” Wesley says of the years of trial and error.He and his compatriots moved on to the idea of building habitat, to creating a wildlife sanctuary to replace the riparian riverbank lost a century ago to sheet piling, concrete and steep banks. The plants would benefit from the river’s heavy dose of fertilizer runoff. The eastern channel dug around Goose Island was shallow and quiet. While negotiating and working for years for official permission, they had plenty of time for testing prototypes on an informal, DIY basis.“We were, like, please someone let us do this,” says Phil Nicodemus, now Urban Rivers’ research director.At home, patience was wearing thin.“At a certain point, my mom was, like, ‘You got to get ‘em out of this yard’ — 300 stupid pickle buckets,” Wesley says. Other cities have called Wesley and want to talk about building their own floating parks.Manuel Martinez/WBEZ By 2017, he and Urban Rivers cofounders Zachary Damato and Josh Yellin finally got permission from all of the necessary agencies and property owners to install 160 feet of floating garden outside the Whole Foods riverwalk. The island was tethered to the riverbed and could rise and fall with floods and stay in place year-round.The city has committed $3.2 million to the project, much of it to be funded by open-space impact fees paid by developers, to extend the park about 700 feet to Blackhawk Street. The cost would be $50 million for the group’s dream — a 17-acre park along the mile length of the manmade, industrial North Branch Canal, from Chicago Avenue on the south to West Weed Street on the north.Enquist says the project’s success is a result of the group’s “constant, unrelenting enthusiasm. They are following their dream and being successful at it.”Global project, garage-band ethicUrban Rivers, now incorporated as a not-for-profit organization, with Wesley as executive director, has a half dozen employees, relying in part on volunteers.The organization has mostly retained its original garage-band ethic. Offices in the basement of an old Carbit paint factory appear chaotic. A whiteboard counts the number of staff members and volunteers who got dunked in the river — three this year.Wesley recognizes the growing pains that accompany more funding and more responsibility. He grimaces about a coming audit. A side project to build a remote-controlled trash robot to scrape trash from around the island is on hold. Airport security confiscated part of one prototype, and another one sank.Its work could spawn similar projects elsewhere. People from Boston, Baltimore, The Hague and other cities have called to talk about building their own floating parks. Urban Rivers relies on a deep bench of volunteers to take on tasks.Manuel Martinez/WBEZ