Four Fairfield Pond

Ira Rennert's colossal estate in New York City puts the "big" in "Big Apple." Ira is an American billionaire who founded the Renco Group Industries Holding Investment Company, which specializes in smelting and manufacturing.

The mansion is part of Fairfield, a 63-acre estate that is one of the largest in America. It has 20 bedrooms, three dining rooms, 39 bathrooms, three swimming pools, and a 154-seat theater. There is also a recreation area with a basketball court, two bowling alleys, a gym, squash courts, and an on-site power plant. Because the estate consumes a lot of power, a personal power plant was built to keep the lights on.

This is one of the world's most expensive homes.

Owned by Ira Rennert.

Location: New York, USA.

Price: $248 million.