Nothing has happened.

That isn’t the most compelling way to begin a news column. But it is what makes the Oyster Bar ramp hall at Grand Central Terminal among the most imposing, dignified and humanistic public spaces in New York City.

The Metropolitan Transportation Authority has left it alone.

Vast enough for a good-sized cathedral — 302 feet long and 84 feet high — the ramp hall is the brilliant interstitial space, under chandeliers and skylights, between the main concourse and what was once the main waiting room on 42nd Street. Ample ramps converge from east and west. They meet at a great tiled vault, a whispering gallery with astonishing acoustical properties, under a bridge between the concourse and the old waiting room. The vault is a forecourt to the venerable Oyster Bar and the dining concourse.

The grandeur of the ramp hall was seemingly lost in 1927, when the concourse ticket offices were expanded into a new mezzanine that reduced the triumphal portal to a rat hole. Until the 1990s, even the main concourse was a playground for advertisers.

All that changed in the 1998 reclamation of the terminal, designed by Beyer Blinder Belle. In the ramp hall, the mezzanine was removed and the bridge — once enclosed by eight-foot walls — was given a Beaux-Arts-style balustrade that opened up the space.