3. Rutland Gate Mansion — $436 million

The word “mansion” doesn’t do the Rutland Gate Mansion justice. This one-of-a-kind estate in London’s Hyde Park neighborhood boasts 45 bedrooms, a large swimming pool in the basement and underground parking. It even used to have bidets covered in semi-precious jewels, gold-plated waste-paper bins, 41 chandeliers and more than 100 gold-plated tissue holders! In fact, in the 1990s, the entire property was furnished by celebrated Paris-based photographer and interior designer Alberto Pinto’s company during a two-and-a-half year refurbishment. Pinto’s company worked on the house from 1992 until 1994, curating its opulent pieces from all over the world.