Note something striking missing from the picture: gambling. And there are no theaters for Donny and Marie either. Just bars and restaurants and shopping and, oh, yeah, cupcakes and bowling. One of the anchor tenants is Brooklyn Bowl; the other is Sprinkles, the Los Angeles-based cupcake emporium that claims to have kicked off the craze. The Linq — which should partially open on New Year’s Eve this year — is a space purpose-built for a new kind of Vegas visitor. Loveman knows who this visitor is, has his facts, the results of his exhaustive surveys and tests. Hear him list them, dropping a heavy hand on the tabletop as he does so, ring finger tapping against the hardwood: thud-plink.

“Twenty million — thud-plink — that’s how many people walked by this corner, and that was in 2009. You have this mass of humanity and sure — thud-plink — about 30% of Americans will visit a casino and gamble in a given year, but a much higher percentage are shopping, drinking, eating. We’re playing a numbers game — thud-plink. This is a much bigger number.”

Vegas is always reinventing itself to draw new clientele. The big move in the 1990s was to make the Strip family-friendly. The latest craze, spurred by Steve Wynn, is mega-nightclubs and poolside day clubs, with table reservations requiring that guests spend at least $10,000 on drinks. The shifting visitor demographics, however, speak to some still newer breed. Nearly 40 million people visited Vegas last year, more than ever before, but they gambled less and stayed in cheaper hotel rooms. They were also — according to the Las Vegas Convention and Visitors Authority — more affluent and likely to be single. They traveled in smaller groups. And they were younger: For the first time in Vegas’ history, the median visitor age sank below 49 years old, to 45. Many, at Caesars and elsewhere, expect it to dip below 40 in the next decade, and that Gen Y and Gen X spending will account for 52% of visitor revenue by 2015.

Call it the Hangover effect — everyone here already does. The movie, about a trio of men-children and their adventures in the wake of a wild night out, has crystallized what the town represents for this new breed. What happens in Vegas stays in Vegas, yes, but it probably should not be planned. “Visitors are more spontaneous,” Loveman says. “People are walking more than ever before.” The trick is to manufacture just the sort of urban environment they will flock to. One with a flame at its heart that will draw the walking throngs like so many moths. In this case the flame is a 3.5-million-pound wheel of steel.

Focus on the High Roller (Loveman: “In the long history of awful gaming puns, this one isn’t so bad”) and you might miss the subtle engineering of the rest of the space. Sure, the wheel’s observation pods are as big as a conference room and have 300 square feet of glass hand-shaped by a single guy outside Venice, Italy. But the street in which the Linq is built was carefully shaped too.

The width, for example, compares to lanes in Dublin or to Bourbon Street in New Orleans because the architects visited those places and measured them. The walkway is slightly sloped, to subconsciously pull visitors forward. It flattens in the small plazas where you’re likely to linger. The overall effect is meant to be that of an old gathering space such as Boston’s Faneuil Hall.

One of the trickiest elements of the project wasn’t a technical challenge but a philosophical one. Once you get visitors into those observation pods, what do you do about a camera inside? Cameras are everywhere in this town except, notably, hotel rooms and poolside cabanas. Do you put a camera in the pods? Would that ruin the magic? The answer is: yes, you do, but the feed is on delay.

This story is from the September 16, 2013 issue of Fortune.