What was formally the most expensive apartment in the world, the penthouse at One Hyde Park is located in one of the wealthiest areas in the world adjacent to Hyde Park and the Mandarin Oriental Hotel. The Knightsbridge development has 86 residences and were quickly bought up by Russian Oligarchs, Chinese billionaires and Arab sheikhs. The 17,000 sq foot apartment features bulletproof glass, an in-house golf simulator, temperature controlled wine cellars, panic rooms and the entire development is patrolled by guards trained by the British Special Forces.
2. $125 million
Penthouse at The Pierre Hotel, New York City
The 12,000 square foot Penthouse at the Pierre Hotel in New York occupies the 41st, 42nd, and 43rd floors, having 16 rooms, 6 bathrooms and 5 fire places. Located on famous Fifth Avenue, the apartment has 360-degree views over Manhattan, Central Park and the Hudson River. Purchased by its last mega rich owner for just $21.5 million in 1999, the estimated electricity and staff maintenance bill for just one month is around $47,000. Other grand features include a Swedish sauna, three powder rooms, a private elevator, and three kitchenettes as well as a main kitchen.
3. $115 million
One57 Winter Garden Penthouse, New York City
Taking the 89th and 90th floors, the One57 penthouse is 11,000 square feet with six bedrooms, a steam room, a library, and an indoor movie theatre. Residents also have access to the Park Hyatt amenities - which takes up the first 39 floors in the buildings. The penthouse owners however will have their own 20,000 square-foot private amenities floor - with a pool, gym, library and theatre. Other features includes a yoga studio, pet grooming room and a ballroom that can fit up to 200 guests.
4. $100 million
CitySphire Penthouse, New York City
The octagon shaped CitySpire Penthouse on West 56th Street is the highest terraced and most expensive residences in the United States, with 360-degree views over New York City. At 8,000 square-feet, the apartment houses six bedrooms, nine bathrooms, a private elevator, 20-guest dining room, 1000-bottle cellar and an eat-in chef's kitchen. It also features an entirely separate staff apartment on the 72nd floor, accessed via a private service entrance. From the penthouse's 135 windows it's possible to see nearly all of New York's bridges, and the coveted Central Park View.
5. $95 million
432 Park Avenue Penthouse, New York City
The next most expensive residence is located on Manhattan's billionaire row between 56th and 57th streets, 432 Park Avenue will be 96 storeys, making it one of the tallest residential buildings in the Western Hemisphere. It will feature a private elevator, fireplace, heated floors, chef's kitchen and a wine cellar. With giant 10 x 10 foot windows residents will have some of the best views in the city.
5. $90 million
South Bank Tower Penthouse, London
Originally a 30-storey structure, the building has since being transformed into an expensive 41-storey residential development with 191 apartments and office space. The building sits on the famous River Thames and over looks the London Eye. The 5,200 square foot penthouse has two levels and two rooftop terraces. Other features include a champagne bar, indoor-outdoor water feature and a levitating dinning table.
6. $60 million
Opus Apartment Penthouse, Hong Kong
The 6,200 square foot penthouse was designed by famed architect Frank Gehry, with the entire building comprised of just 12 units, each with their own private pool. Set high in the hillside, the apartment has an incredible view of the city and features winding glass columns down the sides. Due to the twisting nature of the building each floor has a different layout, making each of the 12 mega rich residences unique.
7. $47 million
Clermont Residence Super Penthouse, Singapore
The Clermont Residence is one of the largest penthouses on the list at a staggering 21,108 square feet. The home is three levels with a five-room Housing Board flat, and will come with a dedicated private lift, pool and a glass-floored cantilevered balcony. Due for completion in 2016, the penthouse is perched atop the 290-metre Tanjong Pagar Centre - Singapore's tallest building.
8. $47 million
56 Leonard, New York City
Figures sourced: Huffington Post