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.