New York (AFP) - Infinity pools, climate-controlled wine cellars and golf simulators -- it's the little things that count in the booming market of luxury real estate coveted by the super-rich in New York.

This year, record prices crossed the threshold of $100 million for a single apartment, and agents are investing more time and trouble than ever before in tailor-making residential buildings for billionaires.

A perfect example is the duplex at the top of a 43-story tower near the United Nations -- nearly 10,000 square feet (more than 900 square meters) with an infinity pool on the terrace, a private elevator and spectacular views.

It's on offer for $70 million.

The building, 50 United Nations Plaza, taps into the latest trend of going above and beyond in the competitive world of luxury living.

It has a state-of-the-art gym, sauna, a shared indoor pool and a rare luxury in Manhattan -- a "private motor court" where cars can drop passengers. Of course, each apartment has a parking space, and there is even valet parking.

"I think we are always looking for ways to distinguish our properties," says Jill Mangone, director of sales for the building.

"There is a movement towards amenities that respond to people's real needs and lifestyle. They want a terrific gym, they want the views, they want extra storage spaces, they want playrooms for children.

"As the buyers become more sophisticated and savvy, they are like, ok, what amenities do really improve my life on a daily basis?"

Over the years, 24-hour doormen, laundry services, gyms, basketball courts and swimming pools have become commonplace in New York.

- Distinguishing features -

At the upper echelon, yoga and dance studios, golf simulators, bowling alleys, movie screening rooms, kennels and enormous reception areas with spectacular views are becoming increasingly common.

At 443 Greenwich in Tribeca, a former factory converted into 52 enormous apartments, the most expensive costs $53 million.

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Residents have access to a steam room, an interior courtyard, landscaped roof deck, wine cellar, a children's playroom... and an underground garage in 1930s style which guarantees "absolute privacy," says Nathan Berman, founder of Metro Loft developers.

In the same area, the 19th century Cast Iron House has been refashioned into luxury apartments, offering a "hydrotherapy spa modeled after a Turkish-style hammam," plunge pool and rainforest shower.

"It was important that this serve as a retreat and a private oasis for residents in a busy city," said a spokeswoman.

The concept is pushed to the hilt at 45 East 22nd Street, a 65-story tower not far from the Flatiron Building with five floors dedicated to relaxation: a library, a fitness center with boxing equipment, golf simulator, basketball court, a children's playroom, a billiards room and a card room.

On the 54th floor, there is a huge reception space with breathtaking views and two kitchens.

"It is not only five floors of amenities, but it's also this unusual concept that I had, to create a club on the 54th floor," said 45 East 22 developer Ian Bruce Eichner.

- $850,000 for parking -

Eichner says he made a "calculated decision" to sacrifice very expensive real estate at the top of the building to allow residents buying less expensive units to have access to the same kind of luxury.

He explains that it is an opportunity for them "to basically enjoy the same views and the same experience as someone who is buying a full floor apartment, for $25 million."

Instead of a swimming pool, which he says risks becoming crowded, he prefers a "fully automated garage," where residents can park a car on a platform that then descends underground.

Near Central Park, there is 520 Park Avenue where a triplex of about 12,400 square feet costs $130 million and also offers a sauna, steam room, children's playroom and climate-controlled wine cellar.

Luxuries are also on offer in the rental market.

MiMA, in Midtown, offers renters a Dog City pet spa that offers indoor and outdoor play spaces, grooming, shampoo and massage services, a vet and the best in professional training.

But all the extras are not cheap.

At 50 UN Plaza, a parking space costs an initial $150,000 and more than $295 a month -- a relative bargain compared to parking at 443 Greenwich, which costs an eye-watering $850,000.

Individual climate-controlled wine cellars cost $50,000 to $75,000 at 50 UN Plaza, and sometimes as much as $200,000.

Activities at "Dog City" at MiMA can easily cost $500 a month.

In the land of the super-rich, even the underground storage units can cost $25,000 to $75,000 depending on their size.