A wide-eyed Mike Pacini stepped off the platform into thin air, his feet dangling as gravity and the cable above his head carried him the length of two football fields in a matter of seconds.

The Boulder City councilman doesn't like roller coasters, but he loved his first ride on the city's new zip-line attraction.

"That was incredible," Pacini said. "This gives you a chance to really fly."

And that was just the bunny slope.

When Bootleg Canyon Flightlines opens for business in a month or so, it will carry tourists, four abreast, down a series of overhead cables that start at the crest of the mountain range between Boulder City and Henderson.

From there, riders will drop about 1,000 vertical feet as they cross almost a mile and a half of rugged desert like birds without all the flapping.

"You won't get this experience anywhere," said Ian Green, the man behind the project. "It'll be the most spectacular trail in North America."

Green is president and co-founder of Greenheart Conservation Co., a Canadian eco-adventure firm that also specializes in treetop, suspension-bridge-style trails known as canopy walkways.

Greenheart has already built so-called "aerial trails" in Canada, Guyana, Nigeria and Haiti. Additional projects are under way in parks or protected areas of Rwanda, Brazil, Peru and Green's hometown of Vancouver, British Columbia.

Green hopes to open the Boulder City attraction by July 4.

"I haven't given a birthday gift to America yet," he said.

The training line that Pacini rode is now in place, as is the lowest of four main cable runs. Greenheart Project Manager Rex Owen expects to string cable on the remaining runs later this week.

Once the lines are up, they will have to be adjusted to get the speed and the tension right.

Green and company use mannequins, bags of cement and the occasional human test subject to fine-tune the system, tracking their progress with the same sort of radar gun you might point at a fastball or a speeding motorist.

Crew member Scott Stemmer, who occasionally likes to ride the cable upsidedown and without a harness, proudly shared his top speed on the 833-foot training line: 43 mph with a stiff tailwind.

"I wouldn't even be working here if I didn't get to mess around a little," said Stemmer, a former Marine who has signed on as the attraction's head tour guide.

The project has been in the works for more than two years, in part because of the challenging nature of the terrain.

A helicopter had to be brought in to deliver a rock drill and construction materials to build the launch platform for one of the lines.

Green said he briefly questioned the wisdom of what they were doing as he watched the helicopter lower the drill onto a narrow ledge of loose rock.

"We didn't design something simple," he said.

The attraction was originally expected to cost Greenheart about $1 million. Now it looks like the final price tag could exceed $1.5 million.

Boulder City owns the land beneath the zip lines, so Green's company has entered into a 30-year concession agreement that will pay the city $100,000 a year plus $10 for each person who pays to ride.

City officials have not yet decided what to do with the revenue, but Pacini said he would like to see it used to help sustain the park.

You may not have heard of it, but Bootleg Canyon is already famous among helmeted lunatics who like to climb onto bicycles and hurl themselves down trails better suited to bighorn sheep.

With descriptive trail names like "Armageddon" and "Poopshoot," the downhill mountain-biking mecca has won international acclaim.

Even so, the city has struggled to find money to support and expand the amenities there.

"Parks are one of the services we provide, but ... they are a draw on the bottom line," Pacini said. "Ian and these guys are working a miracle. They're taking a piece of ground and turning it into a money maker."

The flight-line ride and guided eco-tour is expected to last 21/2 to 3 hours and cost $149 per person. Boulder City residents will get a 25 percent discount.

After a quick trial run on the comparatively short and tame training line, customers will be shuttled to the antenna-studded summit of Red Mountain. There, they will drink in panoramic views of Las Vegas, Lake Mead, Boulder City and the Eldorado Valley as they steel themselves for their first big drop, a 1,850-foot run down the face of the mountain at a nearly 17 percent grade.

The next two runs are longer still, cutting across the red cliffs high in Bootleg Canyon, then swooping over the bike trails on nearly half a mile of cable.

Customers won't be able to pick and choose which zip lines they ride. The course is laid out such that once you go down the first cable, your only route back to civilization is to ride the other three.

"Unless you want to walk back," Stemmer deadpanned.

Short hiking trails and observation points between each zip line will allow riders to pause and take in the view.

Stemmer and other guides will be on hand to point out interesting features in the landscape.

Green describes it as a "conservation-based attraction" designed to thrill visitors and leave them with a new appreciation for their desert surroundings.

Of particular interest to him are the tourists who normally wouldn't get out of their rental cars, let alone venture onto a remote outcropping.

Of course, there can be a fine line between observing nature and trampling it.

State wildlife officials worry that drawing more people into the River Mountains could further stress a herd of about 250 bighorn sheep that is already being squeezed on all sides by highway expansion and new development.

"We're always concerned with anything that might increase human activity in proximity to that particular sheep herd," said Nevada Department of Wildlife spokesman Doug Nielsen. "It's kind of like a herd with a noose around its neck."

"You just wonder how much those poor critters can take," said Nielsen, a former game warden who writes an outdoor column for the Review-Journal.

Green is sensitive to such concerns.

He said his firm was careful to confine the project to "an area that's already been impacted" by the bike trails and other human activity in Bootleg Canyon.

Ultimately, though, the most effective way to get people to preserve a natural wonder is to show it to them, Green said.

"These kinds of trails, whether in Guyana or here, they open people up to nature."

The experience seemed plenty eye-opening to Pacini.

"We gotta do that again," he said as he was unhooked from the training line. "Holy (expletive), and you can quote me on that."

Contact reporter Henry Brean at hbrean @reviewjournal.com or 702-383-0350.