EDITOR'S NOTE: This story has been changed from the print version to clarify details about Hudson Pacific's planned Icon project.

However dazzling an image Hollywood has projected to the outside world, locals know the truth: For a long time, it was more grit than glam.

Until the turn of the century, the 3.5-square-mile neighborhood was a haven not only for flocks of tourists but also for crime, grime and more homeless youth than any other place in Los Angeles.

“When I came here 21 years ago, things were in a sad state of affairs,” said Leron Gubler, chief executive of the Hollywood Chamber of Commerce. “People were embarrassed to say they lived here.”

That situation has since changed in a big way. Today, Tinsel Town is starting to live up to its reputation.

Developers have together committed nearly $4 billion to the construction of major projects in Hollywood. More than 25 ground-up construction projects – including as many as 12 towers rising more than a dozen stories each – are in various stages of planning or construction in the area. In addition, at least 10 existing buildings have been slated for extensive renovation, conversion or expansion.

New construction alone promises to add:

• More than 2.2 million square feet of office space, or the equivalent of 1.5 U.S. Bank Tower buildings.

• About 650,000 square feet of retail, or as much as the Grove and the adjoining Farmers Market.

• Up to 4,550 apartment units, about 300 more than the 45-building Park La Brea complex on Third Street.

• Up to 1,050 hotel rooms, as many as L.A. Live’s sleek JW Marriott Los Angeles and Ritz-Carlton Los Angeles hotels combined.

That’s not the end. Beyond the new construction, redevelopment or conversion of existing buildings will renew an additional 540,000 square feet of office space, 420,000 square feet of retail, 437 apartment units and 550 hotel rooms.

The most recent project to reach completion, and one that set a high bar for the area – is the new campus of Boston’s Emerson College. The $110 million building, designed by architect Thom Mayne of Morphosis, was called by Los Angeles Times architecture critic Christopher Hawthorne “one of the first really ambitious pieces of architecture to be finished in Los Angeles since the recession.” It opened earlier this year.

Developers cataloged at least a half-dozen factors that drew them to Hollywood: Its central location, walkability, proximity to transit hubs, the nearness of all the major entertainment studios, a diverse employment pool and great amenities.