10 of the world's most expensive homes

Photo courtesy of Hilton and Hyland

The rich are only getting richer, and they've got the real estate to prove it.

For the world's super-wealthy -- not your Angelina Jolies and George Clooneys but your billionaire CEOs and various magnates who are way wealthier than those peons -- the price tag for an appropriate home goes all the way to $1 billion.

Some uber-rich buyers, such as Brazilian-born philanthropist Lily Safra, buy historic estates and add a few personal touches, like their own helipad. But many build a custom palace from the ground up.

Bill Gates spent seven years and a few million dollars on his ultra-nerdy Xanadu 2.0 compound overlooking Lake Washington, and his personal seal is on everything from the high-definition monitors with changing art to the high-tech underwater sound system in his pool. Investor Ira Rennert's neighbors in The Hamptons weren't too happy when he decided to build a $245 million, 110,000-square-foot manse, but he got his bowling alley and personal power plant all the same.

Here are 10 extravagant homes with owners who really understand luxury.

The $135 million Beverly House, Beverly Hills, California

Photo courtesy of Hilton and Hyland

Beverly House, located three blocks from Sunset Boulevard, is currently on the market for $135 million. In the meantime, renters can pay $600,000 per month to get free rein of the lux property. It sits on six flat acres of land and includes a slew of smaller homes in addition to the Italian- and Spanish-style, H-shaped main house. That space features a 50-foot entry hall, intricately carved ceilings, a large library, wrap-around balcony, billiard room, family room with an outer terrace that can seat 400 people, an art deco night club, wine cellar, two projection rooms and spa facilities.

It was designed by architect Gordan Kaufmann and built by banking executive Milton Getz. In 1946, publishing mogul and "Citizen Kane" inspiration William Randolph Hearst moved in and stayed until his death in 1951. Since then, the home has become famous for its roles in films like "The Godfather" and "The Bodyguard."

The $102 million Fleur de Lys Mansion, Los Angeles

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This past March, the Fleur de Lys Mansion sold for $102 million, making it the highest-priced home sale to date in Los Angeles County. It was first listed in 2007 when original owners David and Suzanne Saperstein finished renovating the manse, divorced and moved out. The current owner, who paid entirely in cash and has chosen to remain anonymous, is rumored to be former junk bond king Michael Milken, according to the L.A. Times.

The 12-bedroom, 15-bathroom home, which was modeled after the French castle Vaux le Vicomte when it was built in 2002, has a 3,000-square-foot wine cellar with a tasting room, two-story library, commercial kitchen, cutlery room and spacious ballroom. The property also features a pool, spa and tennis courts. It was used for the film "The Green Hornet," the ABC TV series "Big Shots" and the 2008 Audi Super Bowl commercials.

The $750 million Villa Leopolda, Villefranche-sur-mer, France

Photo courtesy of Flickr user Pierre Omidyar

When Russian billionaire Mikhail Prokhorov attempted to buy Villa Leopolda in 2008, it was valued at a whopping €500 million -- equal to about $750 million at the time. It was built in 1902 by Belgium's King Leopold II, who gave it as a gift to one of his mistresses. Lebanese banker Edmond Safra bought the estate in 1988 and left it to his widow Lily Safra when he died in an arsonist's fire in 1999. She's the current owner.

The 11-bedroom, 14-bathroom villa sits on 50 acres. It features a commercial greenhouse, outdoor kitchen, pool and helipad. It was used for famous films such as "The Red Shoes" and "To Catch a Thief."

The $45 million 15 Central Park West, New York City

Photo courtesy of Wikimedia user LongLiveRock

According to Michael Gross, author of the book "House of Outrageous Fortune: Fifteen Central Park West, the World's Most Powerful Address," this high-end Manhattan building is known as "Limestone Jesus."

That's probably because it's full of the city's most affluent and powerful residents, including hedge fund boss Daniel Loeb, who bought the 10,674-square-foot penthouse at the top of the high-rise for $45 million in 2008. In 2012, rumors began spreading that Loeb was trying to sell the property for $100 million, but he has yet to do so.

The $89.4 million Kensington Palace Gardens, London

Photo courtesy of Wikimedia user Malkalior

Indian steel tycoon Lakshmi Mittal calls this Kensington Palace Gardens home his "Taj Mittal." He bought it for £57 million -- about $89.4 million in today's dollars -- from English business magnate Bernie Eccclestone in 2004. The estate's nickname is only sort of a joke: Mittal renovated it with marble that was sourced from the same quarry as the actual Taj Mahal.

The property is on the tree-lined "Billionaires' Row," where other highly affluent people like Roman Abramovich and Leonard Blavatnik also own property. It has 55,000 square feet of space, 12 bedrooms, a Turkish bath, swimming pool, picture gallery and ballroom.

The $400 million Penthouse at the Tour Odéon, Monte Carlo, Monaco

Photo courtesy of Wikimedia user Odéon

The opulent and shiny 49-story Tour Odéon building hasn't even opened its doors, and already its penthouse has been called the most expensive in the world. Set to open in spring 2015, the 35,500-square-foot apartment is expected to sell for almost $400 million, according to CNNMoney. The 560-foot skyscraper will be the second-tallest building on the Mediterranean skyline once it's complete.

The penthouse will feature a 360-degree view of the water and access to a circular rooftop infinity pool with a water slide.

The $1 billion Antilia, Mumbai, India

Photo courtesy of Wikimedia user Jhariani

Antilia, a 27-story skyscraper on the pricey Altamount Road in Mumbai, is the most expensive home in the world, valued at upwards of $1 billion. Mukesh Ambani, an Indian business tycoon and multibillionaire, moved into the 400,000-square-foot mansion in 2012 with his wife and three children. The modern property was designed by Chicago-based architects Perkins & Will.

Antilia, which was named for a phantom island in the Atlantic, features a multistory garage with space for 168 cars, a ballroom, three helipads, gardens, a temple, guest suites, a health level and a home theater that seats 50.

The $125.5 million Xanadu 2.0, Medina, Washington

Photo courtesy of Flickr user Jeff Wilcox

Bill Gates, Microsoft co-founder and the world's second-richest man, took seven years to custom-build Xanadu 2.0, a modern-yet-rustic, high-tech estate valued at $125.5 million. According to luxury website The Pinnacle List, Gates bought the lot in 1998 for $14 million. It's named after the home of the title character in "Citizen Kane."

The 66,000-square-foot "smart" complex is built into the side of a hill and looks out over Lake Washington. Electronic pins worn by residents and visitors trigger their personal preferences, like the temperature and lighting of a room or even the art that will appear on high-definition monitors throughout the property. It features a 3,900-square-foot pool building, 2,500-square-foot gym, a 2,100-square-foot library with a dome ceiling, a 2,300-square-foot reception hall, a 6,300-square-foot underground garage and many other amenities.

The $195 million Palazzo di Amore, Beverly Hills, California

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Real estate mogul Jeff Greene just listed his 25-acre estate in Beverly Hills for a heart-stopping $195 million, earning the property the honor as the country's most expensive listing. The Palazzo di Amore is a Mediterranean-style villa that tops 53,000 square feet of space, though 15,000 of that is an entertainment complex containing a ballroom with a revolving dance floor. It has 12 bedrooms, 23 bathrooms, a bowling alley, a theater, tennis courts, swimming pools, reflecting pools, waterfalls and a garage that can comfortably fit 27 cars.

All told, the property can accommodate parties for up to 1,000 people, who can spend their time meandering the gardens and vineyards where the property produces its own wine, or walk over floating glass walkways hovering above pools lined with mature olive trees.

The $249 million Fair Field, Sagaponack, New York

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Fair Field, a 63-acre oceanfront compound in The Hamptons, is valued at around $248.5 million. It's owned by billionaire investor Ira Rennert, who started building the sprawling estate in 1999 but couldn't move in with his family until 2004 after plowing through some nasty neighborly controversy.

Nearby residents complained about the project to the Town of Southampton in 1998, claiming that a 110,000-square-foot home would have a negative impact on the neighborhood. After their lawsuit failed, Rennert built the home anyway, but now Southampton homes can't be more than 20,000 square feet.

Fair Field has 29 bedrooms, 39 bathrooms, its own power plant, three swimming pools, a synagogue, two courtyards, an orangery, a 164-seat home theater, basketball court and bowling alley.