You might have wondered why it seems that America’s celebrities always seem to be buying each other’s former homes, especially in and around Los Angeles. It’s relatively simple, really: Los Angeles building ordinances limit the height on the contruction of new walls and hedges. As a result, celebrities tend to trade homes because there’s a limited supply of homes that will give them what they ultimately want: privacy

Regardless of whether the glitterati trade out their homes with each other or have them custom-built, for all the money they have to buy what their hearts desire, the most difficult thing for them to possess is privacy. As a result, they favor homes set away from streets and roads by long, gated drives, tucked away behind woods or in the hills, and outfitted with state-of-the-art guard houses and security systems

The following is a partial list of the Forbes Celeb 100 and the homes they own:

Ryan Seacrest (No. 28 on the Celeb 100), producer and host of “American Idol”, is currently in escrow to buy the former gated Goldwater Canyon compound of actres-comedian Ellen DeGeneres (No. 34) and her wife, actress Portia de Rossi. The property, for which Seacrest shelled out a cool $37 million, includes a main house of more than 9,200 square feet, three guest houses, a pool, and several koi ponds

Degeneres and de Rossi certainly didn’t become homeless, as they not only bought a 4,100-square-foot waterfront home that used to be Brad Pitt’s, but also are reportedly in contract for an 8,500-square-foot Beverly Hills home just down the street from the home they’re selling to Seacrest

Pop star Katy Perry (No. 8) is keeping, for now, her Hollywood Hills home she shared with her ex-husband, actor Russell Brand. The property has a three-story main house at more than 8,800 square feet, a guest house, and patio with swimming pool

Jennifer Aniston (No. 22 on the list) has been quite busy in the past year. She sold her Beverly Hills home, named Ohana, last year for $37 million to move back to her hometown of New York, where she bought neighboring condos for $7 million. However, due to overwhelming paparazzi issues, she sold them for a loss and fled back to the west coast, where she paid $21 million for a Bel Air estate that needs renovating. She didn’t stop there, however, as she also spends $40,000 a month on a Trousdale Estates home

Justin Bieber (No. 3) recently decided to buy a 10,000-square-foot home in Calabasas, California, in the exclusive gated neighborhood The Oaks. This came after he was about to buy a Hollywood Hills lakefront masterpiece made of glass, steel, and concrete before having it bought out from under him by actor Ashton Kutcher (No. 51 on the Celeb 100), who had been leasing the 9,400-square-foot home

NFL star Tom Brady (No. 59) and his model wife Gisele Bundchen (No. 61) are listing their Boston penthouse for $10.5 million and moved into a monstrous 22,000-square-foot mansion in the chic Los Angeles suburb of Brentwood. The new digs boast eight bedrooms, a six-car garage, an elevator, and a weight room, among other amenities.