When the Four Seasons Hotel New York opened in 1993, architect I. M. Pei wasn’t entirely satisfied—budget limitations kept him from creating the swish penthouse he envisioned for the 52-story, limestone-clad tower. But shortly after Ty Warner acquired the property in 1999, he enlisted Pei and New York-based Peter Marino to create a crown jewel befitting the city’s tallest hotel.

Seven years and $50 million later, mission accomplished. In July, the hotel Marino designed the sumptuously appointed interiors, which feature walls dressed in book-matched Chinese onyx; closet doors wrapped in buttery leather; and a 4-foot-tall, fiber-optic chandelier made of glass chards. Pei’s contribution includes four glass terraces that float 700 feet above the street.

At $30,000 a night, the suite is reportedly the world’s most expensive. A stay includes personal butlers, in-room spa treatments, and unlimited use of the hotel’s Rolls Royce and Maybach automobiles. The room has been booked on only four occasions since its opening, but such limited usage appears to be the point. “This type of suite shouldn’t be rented on a very frequent basis because it’s so precious,” says Leslie Lefkowitz, the hotel’s public relations director. “We want to keep the exclusivity and maintain the pristine condition of the room.”