(Photo: Damon Winter/The New York Times/Redux)

I had my first encounter with the primitive horrors of the subway system as a child in the 1970s: air like hot wax, graffitied trains shrieking in pain, tiles scummed with the grease of ages. That vast infernal warren has improved so radically since then that the concept of an underground park called the Lowline is not entirely bizarre. Yet we still scrabble down the same dim gopher holes and face rush hour with a tremble.

Which is why the opening of Fulton Center feels so celebratory: A beacon of daylight has brought well-being to an especially tangled node of misery. A conical dome designed by Grimshaw is lined with an ingenious fishnet fitted with reflective panels. This tour de force of natural illumination, by James Carpenter, grabs sunshine from the sky and tosses it down to the platforms, turning a pit into a light box and crowning the space. In the spirit of a Tiepolo ceiling, the oculus draws even the hurried eye heavenward for a quick blast of spectacle, just long enough to slow your step and define the difference between a passage and an actual place.

Fulton Center tries to compete with Grand Central and the coming World Trade Center hub as an indoor civic space, with some of the same rarities: comprehensible signage, cleanliness, art, and, soon, shops and food. Yet it discourages lingering, the measure by which we judge public space. The cascade of escalators, the glass-and-steel palette, the polished concrete floors, and the digital images dancing across endless screens�all are hyperactive in quality, designed to speed crowds through. That’s okay. New York has other hangout spots, and Fulton Center offers something much rarer: a civilized portal to the underworld.