Back in 2004, Facebook was still a post-dormroom project on wobbly colt legs, being coded by true believers, pulling all-nighters from rented living rooms around Palo Alto. Now, the company has 1,200 employees, recruited and supported by a professional human resources manager, and lives in a 150,000-square-foot headquarters that is more reminiscent of an early Google or Microsoft than a scrappy start-up. “Yeah, we’ve come along way,” says CEO Mark Zuckerberg.

But the spirit of the original Facebook -- do things fast, take risks, don’t be afraid to break things to make them better -- still lives on, even as their surroundings have become more grown-up. “We’re an entrepreneurial company,” says Andrew Bosworth, a coding legend who runs a “boot camp” for new engineers. “This place is fast paced and free form. If you’re not coming up as a new ideas, then you’re just along for the ride.” The working environment is designed for, and modified by, people who toil long hours (all-nighters are still routine) and find that creative, often irreverent, self-expression to be as important as the copious free food.

At 400 million active users worldwide, Facebook has long shaken off its college roots. But the spirit of dorm-room expressiveness lives on at the company's new headquarters. And, as you will see, urinals are a recurring theme.

Male Facebook employees vanquish distractions as they modulate their exemplary hydration levels maintained by the free beverages.

Employees keep long hours, and often let off steam together. More than one meeting room has game or musical equipment, though this one is reputed to be the location of more than one ill-advised performance video.

Mark Zuckerberg commissioned graffiti murals for the company's original offices that dotted Palo Alto's University Avenue. "I really didn't want the place to feel corporate," he said. Many of the original works were cut from the walls and now adorn the new building.

The customer service team--who help with everything from user tech support to site safety--under a reminder that while the site is up, the work never ends for them.

Nobody uses Facebook for the design, says designer Soleio Cuervo, "The purpose of the site is to draw your attention to the people you know and care about." But aesthetics matter. Design, color, spacing, are points of obsessive pride. "We even created our own font."

Quiet meeting rooms line the perimeter of the floors, where staffers hold meetings, use the phone, think, or prepare their next hackathon strategy.

Someone uses or logs in to Facebook from every country on earth, and the international team is visibly proud. Facebook works with more than one million developers and entrepreneurs from more than 180 countries, and the site is found in more than 70 language, including Latin.

One of the unsung perks of working at Facebook: You won't get fired for being on Facebook at the office.

Micro-kitchens abound, filled with every kind of beverage or snack available. Free, of course. And a full barbecue on the roof. And a pastry chef.

Pop culture mavens have a home at Facebook--even Tyra Banks made a site visit recently.