Penthouse D, One Hyde Park, London

Penthouse D atop London's super-luxury high-rise One Hyde Park has no public real estate listing. The 18,000-square-foot mega-apartment. CPC Group, owned by Candy's brother, Christian Candy, and Waterknights, a firm headed by former Qatar Prime Minister Sheikh Hamad bin Jassim bin Jaber Al Thani, developed the building. Candy & Candy, the brothers' firm, did the interior design.

The formal reception area boasts a sparkling wave of Swarovski crystals hung from the ceiling. The chandelier is both a sculpture and a chandelier, with hundreds of unique crystal strands illuminating the enormous chamber. A fresco depicts the London skyline and the network of walkways that run through the park below on one wall. A big glass fireplace sits in the center of the artwork. The owner's room has a glass panel wall that faces the reception area and offers panoramic views of the park.

Two matching baths in Nero Marquinia marble can be seen in the sleeping quarters. Black marble floors contrast with white Statuario marble-covered walls in the "her" bath. The color palette of the "his" bathroom is flipped, with noir walls and milky white floors. Lalique, a French glassmaker, created bespoke fittings for both bathtubs. The penthouse and its two wraparound terraces offer stunning views of Hyde Park, one of London's most famous royal parks. It is also the largest, with a total area of 350 acres.

Price: $237 Million