The owners of the world’s most luxurious houses can be a mysterious bunch. We all know who owns Buckingham Palace, but does anyone recognize the name Tim Blixseth? Or know the Indian billionaire who built a 27-story apartment building just for himself? We’re guessing not.

Well, the mystery ends here. we’ve got a rundown of the world’s 10 most expensive houses—modern castles, really—and the people lucky enough, and rich enough, to own them.

If you’ve got a spare few million lying around, these incredible places could be right up your street.

Feast your eyes on some of the priciest homes on the planet.

Top 10 Costliest Houses In The World

1.Antilia, Mumbai, India

 Owner: Mukesh Ambani, worth $21.5billion

Value: upward of $1 billion

The twenty-seven story, 400,000-square foot skyscraper residence, named after a mythical island in the Atlantic, has six underground levels of parking, three helicopter pads, a ‘health’ level, and reportedly requires about 600 staff to run it. It is the world’s most expensive home far and away with construction costs topping $1 billion.

2.Villa Leopolda, Villefranche-sur-mer, France

Owner: Lily Safra, worth $1.2 billion

Price: 500 million euro ($750 million at the time) in 2008

King Leopold II reportedly built a series of waterside homes for his many mistresses. This 20-acre estate was valued at 500 million euros in 2008, when Russian billionaire Mikhail Prokhorov attempted to buy it. He eventually pulled out of the deal, forfeiting a 50 million euro deposit.

3.Fair Field, Sagaponack, N.Y.

 Owner: Ira Rennert, worth $6.5 billion

Property value: about $248 million, according to 2012 tax assessments

The industrial billionaire’s hulking 29-bedroom, 39-bath Hamptons compound has not one, but three swimming pools, plus its own power plant on premises.

4.Kensington Palace Gardens, London, U.K.

 Owner: Lakshmi Mittal, worth $16.5 billion

Purchase Price: 117 million pounds ($222 million at the time) in 2008

The steel magnate is believed to own three homes on the high-security street known as Billionaires Row, including a neo-Georgian mansion near the Israeli embassy. The home (not pictured), rumored to have been purchased for Mittal’s son, was sold by hedge fund billionaire Noam Gottesman.

5.One Hyde Park, London, U.K.

 Owner: Rinat Akhmetov, worth $15.4 billion

Sale Price: $221 million in 2011

The world’s most expensive apartment, located in posh Knightsbridge, was purchased by the Ukraine’s richest man. It boasts a staggering 25,000-square feet, bullet proof glass and 24-hour hotel concierge service.

6.Ellison Estate, Woodside, Calif

 Owner: Larry Ellison, worth $43 billion

Value: estimated $200 million to construct

The Oracle founder, arguably the world’s most avid collector of real estate, built his 23-acre Japanese-style estate in 2004 with 10 buildings, a man made lake, a tea house, a bath house and a koi pond. The property is currently assessed at just over $70 million.

7.Kensington Palace Gardens, London, U.K.

Owner: Roman Abramovich, worth $10.2 billion

Purchase Price: 90 million pounds(about $140 million) in 2011

The Russsian tycoon owns several huge London estates (not pictured), including a Billionaires’ Row mansion. Since purchasing, plans to build a subterranean extension that includes a tennis court, health center and auto museum were approved by the city. He also owns a French Riviera chateau and in 2009 spent a record $90 million on a 70-acre estate on St. Bart’s.

8.Blossom Estate, Palm Beach, Fla

Owner: Ken Griffin, worth $4.1 billion

 Total Purchase Price: nearly $130 million in December 2012

The hedge fund titan purchased four side-by-side properties totaling eight acres on the ocean. Three lots tout houses while the fourth was already torn down; the entire swath of property was once used as a single estate.

9.Xanadu 2.0, Seattle, Washington

 Owner: Bill Gates, worth $67 billion

Market Value: $120.5 million, according to 2012 tax assessments

The high-tech Lake Washington complex owned by the world’s second-richest man boasts a pool with an underwater music system, a 2,500- square foot gym and a library with domed reading room.

10.Mountain Home Road, Woodside, California

Owner: reportedly Masayoshi Son, worth $8.6 billion

Purchase Price: $117.5 million in 2012

The most expensive home sale on record includes a 9,000-square foot neoclassical house, a 1,117-square foot colonnaded pool house, a detached library, a retreat building, a swimming pool, a tennis court and formal gardens.