The steel gate on East 56th Street, near Second Avenue, stands 14 feet tall and stretches 30 feet long. What’s behind it, you ask? To find out, you will have to be walking by when a car pulls up and the doors part, revealing a 3,000-square-foot porte-cochere, with a cobblestone floor and a soaring, swirling white center column. After the car (or maybe it’s a motorcade, the space is large enough to accommodate six vehicles) slips in, the opulent world within 252 East 57th Street, a condominium that opened in March, will be concealed from you again.

Welcome to Manhattan in the new Gilded Age, where condos offer wealthy buyers not just decadent indulgences — A wine cellar! A stroller valet! — but also the privacy usually associated with a gated mansion in Greenwich, Conn., not a 65-story tower in Midtown Manhattan. The rest of us can only crane our necks to catch a glimpse of a cloistered world out of reach.

Wealthy buyers want privacy in all caps. Vehicle-friendly entrances have their roots in the last Gilded Age, when buildings like the 1884 Dakota on the Upper West Side provided a roof overhead for those arriving and departing in carriages. The private drive came roaring back into fashion when 15 Central Park West opened in 2007. Now, porte-cocheres, circular driveways and gated courtyards are cropping up in Manhattan developments aimed at buyers looking to avoid flashing paparazzi cameras, or anyone who might gawk. A TriBeCa condo, 443 Greenwich Street, has become a celebrity magnet in part because of its private underground valet entrance.