After 45 years overseeing his entertainment empire from the comfortable confines of the opulent Playboy Mansion, Hugh Hefner has become a tenant. Last August, the 90-year-old founder of Playboy magazine sold the property via his Playboy Enterprises to private equity investor Daren Metropoulos for $100 million, with the caveat that Hefner can lease it for $1 million a month.

Metropoulos—whose firm owns the Hostess snack company—is buying more than just a 29-room luxury residence. Throughout the decades, the Mansion has been seen as the ultimate destination for decadence and sexualized socializing. Check out 15 facts about its history, the secret tunnels built for celebrities, and why Mike Tyson won't be attending movie night anytime soon.

1. IT WASN’T THE FIRST PLAYBOY COMPOUND.

When Hugh Hefner produced the first issue of Playboy in 1953, he toiled from a kitchen table in a small Chicago apartment. By 1959, the magazine had become so successful that he was able to take over a Chicago mansion, outfitting it with an indoor basement pool and a bedroom-slash-office with a 100-inch diameter bed; Playboy models and nightclub employees could rent rooms on the third and fourth floors for $50 a month. (No male visitors were allowed.)

After buying the real estate where he built the Los Angeles mansion for $1 million in 1971, Hefner shuttled between both before making a permanent move to the West Coast in 1974. After stints as an art school and student dorm, the Chicago building was converted to a seven-unit condominium in 1993.

2. PLAYBOY ONCE CLAIMED THAT CELEBRITIES USED SECRET TUNNELS FOR VISITS.

The 1970s saw a number of celebrities use the Mansion for decathlons of decadence, but not everyone wanted to be seen coming and going. In late March 2015, Playboy.com, reported that Polaroids and blueprints were discovered detailing an underground network of tunnels running from the property to the homes of famous guests like Warren Beatty, Jack Nicholson, and James Caan. Elaborate design? More like an elaborate hoax: On April 1, 2015, Hef came clean that the "blueprints" were an April Fool's joke.

3. JOHN LENNON ONCE ASSAULTED A PAINTING THERE.

The Mansion doubles as an impressive art gallery for art aficionado Hefner, but one former Beatle wasn’t too appreciative. During a visit to the Mansion in the 1970s, John Lennon allegedly became a little belligerent and extinguished his cigarette into a work by Henri Matisse. Hefner restored the illustration; Lennon was presumably allowed to continue visiting.

4. IT HAS ITS OWN PET CEMETERY.

With both its own zoo license and dozens of pets roaming the Mansion over the years, Hefner thought it would make sense to keep a resting place for animals on the grounds. Many of Hefner’s personal canines have been buried there; so have many of the Mansion’s several monkeys and 50-plus varieties of birds. One tombstone reads, “Teri, Beloved Woolly Monkey.”

5. THE PLACE IS BOOBY-TRAPPED.

In his autobiography, The Unusual Suspect, actor Stephen Baldwin recalled the time that he and Robert Downey, Jr. descended a spiral staircase to hang out with Playmates and possibly indulge in semi-legal substances in the wine cellar. When Downey reached the third-to-last step, he turned to Baldwin and told him not to step on it because it would trigger a silent alarm. The feature might have been a holdover from 1927, when the cellar was in use as a boozy storage room during Prohibition.

6. LUKE WILSON WAS BANNED FROM THE PREMISES.

Actor Luke Wilson admitted to press in 2006 that some modest misdirection while talking to Mansion staff got him “DNAed”—tagged with a Do Not Admit label. Wilson said a Mansion employee asked who he was with one night and Wilson lied by saying it was his brother, Owen: It was actually a friend. Wilson was denied entry for 18 months before he groveled and was allowed back in.

7. SOMETIMES GUESTS WOULD JUST MOVE IN.

The amenities of the Mansion were such that several of Hefner’s guests over the years considered it a staycation. James Caan moved in for a bit in the 1970s; so did Shel Silverstein and Tony Curtis.

8. IT’S HOSTED BOXING EVENTS.

Hefner has opened up the Mansion several times to host professional boxing and mixed martial arts events. Boxers like David Haye, who were accustomed to fighting in front of large Las Vegas crowds, found it slightly disarming to compete in front of just a few hundred spectators, many of them celebrities; Hefner thumbed his nose at women competing, telling The Guardian in 2003 that he had “mixed” emotions about females fighting.

9. HEFNER HAS AN IN-HOUSE BIOGRAPHER.

Chronicling the many seminal moments in Hefner’s life is the duty of Steve Martinez, a full-time archivist who painstakingly updates and maintains the nearly 3000 volumes of scrapbooks kept in the Mansion’s library. Martinez collects photos and information during the week; on weekends, he and Hefner update the books. The volumes begin with portraits of Hefner at six months; the subject has left instructions that the final volumes be filled with his obituaries.

10. THE GROTTO ONCE MADE PEOPLE REALLY SICK.

Hefner has had to endure many jokes over the years about the alleged petri dish that is the grotto, the Mansion’s man-made cave that includes a whirlpool. In April 2011, it stopped being funny: 123 people who visited the attraction over a weekend for a fundraiser became ill, with health officials identifying the bacteria that causes Legionnaires’ disease in the water. Symptoms included fever, headache, cough, and other flu-like ailments.

11. IT EMPLOYS OVER 80 STAFF MEMBERS.

With 21,000 square feet to attend to, there’s no skeleton crew: Playboy employs over 80 full-time workers to tend to the grounds, cook, provide security, and maintain electrical and plumbing services.

12. MIKE TYSON BROKE MANSION RULES.

Hefner takes the Mansion’s regularly-scheduled movie nights very seriously. A lifetime film buff, he has a board of friends curate titles for screenings and has a zero-tolerance policy when it comes to disruptions during their running times. Once, Mike Tyson was invited to attend a film. After sinking into a leather couch, he fell asleep, ignoring his phone that kept ringing incessantly. It was Tyson’s first and last invitation to the movies.

13. GUESTS ARE GREETED BY FRANKENSTEIN’S MONSTER.

Visitors bearing an invitation to the Mansion are brought through iron gates to the entrance, where they announce their presence to a giant rock housing an intercom system. Once inside, guests idle for a bit in the Great Room, a foyer containing several portraits of Hefner and a giant statue of Frankenstein’s monster.

14. HEFNER HAS A CARDBOARD STAND-IN.

When a dinner gathering or party is in full swing and Hefner can’t attend, a life-size cardboard cut-out of him can usually be seen looming over the proceedings.

15. LARRY FLYNT ALMOST BOUGHT IT.

Free speech advocate/Hustler founder Larry Flynt expressed interest in buying the Mansion early in 2016, with plans to convert it into the “Hustler Mansion.” While it’s not known whether a formal offer was ever made, Flynt conveyed through associate Harry Mohney that Hefner would not be welcome to remain. As it stands, Hefner's deal includes being able to remain in residence until his death.

All images courtesy of Getty Images.