Even though looking at these houses makes us insanely envious, we are intrigued. These extravagant places are out of this world, and we can't even begin to imagine living there. Take a look at the 10 most expensive homes ever. We can't believe people actually own them!

​10. 7 Upper Phillimore Gardens


This London 10-bedroom prep school turned mansion has an underground swimming pool, a sauna, gym, movie theater, and panic room. The interior is covered in marble, gold, and priceless artworks. 

It is valued at $128 million.

Olena Pinchuk, daughter of the Ukraine's second president owns the mansion. She is the founder of the ANTIAIDS Foundation.

9. Kensington Palace Gardens


This pad is located on London's Billionaires Row, and will soon add an underground extension with a tennis court, health center, and auto museum. 

It is valued at $140 million.

Roman Abramovich, a Russian billionaire who owns the English Premier League's Chelsea Football Club, owns the house.

8. Seven The Pinnacle


This Montana home is the largest property in the Yellowstone Club, a private ski and golf community. The house has heated floors, multiple pools, a gym, wine cellar, and its own ski lift.

It is valued at $155 million.

The owners are Edra and Tim Blixseth. Tim is a real estate developer and timber baron, who confounded the Yellowstone Club.

7. Hearst Castle


This California castle has 27 bedrooms, and has been used in the movie 'The Godfather.' Famous figures like John and Jackie Kennedy, Clark Gable, and Winston Churchill have stayed here.

It is valued at $191 million.

William Randolph Hearst's trustees now look over the castle, which is a tourist site and part of the California Park System today.

6. Ellison Estate


This California compound is a 23-acre property with 10 buildings, a man-man lake, koi pond, tea house, and bath house.

It is valued at $200 million.

The co-founder of Oracle and the Forbes' third-richest man in the world from 2013, Larry Ellison, is the owner.

5. 18-19 Kensington Palace Gardens


This other property on Billionaires Row in London, 18-19, has 12 bedrooms, Turkish baths, an indoor pool, and parking for 20 cars. It sits alongside the home of Prince William and Kate Middleton.

It is valued at $222 million.

The owner is Lakshmi Mittal, the head of Arcelor Mittal, the world's largest steel manufacturer. Mittal is one of Forbes' 100 richest men in India.

4. Four Fairfield Pond


This New York home has 29 bedrooms, 39 bathrooms, a basketball court, bowling alley, squash courts, tennis courts, three swimming pools, and a 91-foot long dining room. It sits on 63 acres.

It is valued at $248.5 million.

The owner is Ira Rennert, owner of the Renco Group.

3. Villa Leopolda


This 50-acre estate in France includes "a commercial sized green house, a swimming pool and pool house, an outdoor kitchen, helipad, and a guest house larger than the mansions of most millionaires," according to Variety. The house was famously used as a set in the 1955 Hitchcock classic "To Catch a Thief."

It is valued at $750 million.

It is owned by Lily Safra, a Brazilian philanthropist and widow of Lebanese banker William Safra.

2. Antilia


This 27-story, 400,000-square-foot building in India has six underground parking floors, three helicopter pads, and requires a 600-person staff just to maintain it.

It is valued at $1 billion.

It is owned by Mukesh Ambani, India's richest man, with a net worth of $23.6 billion, according to Forbes.

1. Buckingham Palace


Technically still a house, the Queen's residence has 775 rooms, including 19 state rooms, 52 bedrooms, 188 staff rooms, 92 offices, and 78 bathrooms. 

It is valued at $1.55 billion.

The British Sovereign owns the palace - currently with Queen Elizabeth II.