In “Report on ‘Grand Central Terminal,’ ” a short science fiction story by Leo Szilard, a Hungarian émigré physicist who helped develop the atomic bomb, researchers from another planet explore Manhattan after a neutron bomb destroyed all life. Their conflicting interpretations of what life was like climax as they investigate earthly artifacts in Grand Central. “What its name ‘Grand Central Terminal’ meant we do not know,” the narrator acknowledges, “but there is little doubt as to the general purpose which this building served. It was part of a primitive transportation system based on clumsy engines which ran on rails and dragged cars mounted on wheels behind them.”

Good guess, but the scientists are largely baffled trying to come to grips with the reasons behind pay toilets and the disks that must be deposited to enter them. One researcher concludes that “a system of production and distribution of goods based on a system of exchanging disks cannot be stable, but is necessarily subject to fluctuations vaguely reminiscent of the manic-depressive cycle in the insane.” The narrator demurs, revealing that a spot check of lodging houses found no “depositories” equipped with “a gadget containing disks” and suggests that they are associated with a ceremonial act “connected with the act of deposition in public places, and in public places only.” Never had so much profundity been expended on a restroom.

GRAND CENTRAL HAS BEEN A SHOWCASE for what the architects of its restoration pronounced “a fascinating fabric of cultural history.” The North Balcony lured so many travelers seeking serenity and contemplation and “itinerant sophists” that it was dubbed the “Philosophers’ Gallery.” A prototype of the DeWitt Clinton locomotive was exhibited on the East Balcony, and in 1929 the Bremen, an all-metal monoplane with a 58-foot wingspan, the first to fly westward across the Atlantic, was suspended over it. Grand Central is the nation’s living room and town square. The Main Concourse and Waiting Room could accommodate 30,000 people. A report completed in 1991 by Beyer Blinder Belle, architects of the restoration master plan, declared the concourse “the central hall, the lungs of the terminal, a place of public assembly without parallel in New York City.” If the concourse evoked the broad aisle of a cathedral, it was fitting that in 1931 Episcopal Bishop William Manning launched a campaign from the North Balcony to raise $10 million to complete the Cathedral of St. John the Divine; a one-ton model was installed as a preview of the Gothic Revival structure rising uptown on Morningside Heights.

A year later, an estimated 5,000 well-wishers converged on the terminal to see off New York City Mayor James J. Walker on his way to Albany to face removal charges. (As he proceeded to the Ohio State Limited on Track 34, accompanied by his wife and her poodle, he encountered Joe Jacobs, the manager of Max Schmeling, who had lost his heavyweight title on a close decision to Jack Sharkey earlier that summer. “I hope they don’t hand me the same kind of a decision you got,” Walker quipped.) In 1934, 80,000 people turned out in a single day to inspect the Burlington Zephyr, a new speed king on the New York–to–Boston run. In 1912, 5,000 New Yorkers singing socialist anthems welcomed 100 children whose parents were striking the textile mills in Lawrence, Massachusetts, and in 1941, 10,000 cheering Brooklyn Dodger fans jammed the Main Concourse to welcome their heroes home from Boston with their first National League pennant in 21 years. And later that year, a week after Pearl Harbor, Treasury Secretary Henry Morgenthau Jr. inaugurated a drive to raise $10 billion in war bonds to prosecute the fight against Fascism. A 118-by-100-foot photomontage was installed depicting “What America Has to Defend and How It Will Defend It.” More than 3,000 people attended the unveiling of the mural. The ceremony was also broadcast on radio nationwide—“again locating Grand Central as a center of American culture,” as the restoration architects described it.

During the war, thousands of servicemen were deployed from the terminal, which was bedecked with patriotic posters. In 1945, 1,000 people an hour—nearly 15,000 in all—filed through a special seven-car train promoting Victory Loan war bonds to view the original German and Japanese surrender documents.

In 1952, an estimated 30,000 heard President Harry S. Truman speak from a Main Concourse balcony. (That same year, Walter Cronkite anchored the 1952 presidential election coverage from the fourth-floor studio.) In the early 1960s, thousands of spectators watched the CBS News screen above the New Haven’s ticket window to follow the space flights of Project Mercury, whose namesake reigned from the terminal’s façade. A spellbound crowd was glued to a video screen mapping Scott Carpenter’s progress orbiting the earth in his Aurora 7 capsule on May 24, 1962 (As the World Turns, the soap opera produced at the terminal’s CBS studio, was preempted).

In 1971, hundreds of people queued up for two hours or more to place their wagers as the nation’s first off-track betting parlor opened at Grand Central (commuters were already used to a long wait; appropriate to the place, one advertisement proclaimed: “Nothing Brightens the Rat Race Like a Horse Race”). In 1973, John Gallin & Son installed what was billed as the city’s first automated teller machine at the Chase Manhattan branch beneath the 18-by-60-foot Kodak Colorama. The Rolling Stones bestowed their imprimatur on the terminal for a new generation when they announced their Steel Wheels world tour there in 1989, the same year that Ringo Starr, who played the pint-sized Mr. Conductor, introduced Thomas the Tank Engine on public television’s new Shining Time Station series there.

“IN THE EVENT OF A CRISIS,” Ben Cheever wrote, “the big room behind and beneath the gods grows black with crowds.” Three thousand “yippies” from the Youth International Party celebrated spring in 1968 by staging a chaotic “yip-in” on the Main Concourse. They were dispersed by nightstick-swinging police officers after they hurled firecrackers and spun the hands off the information booth’s priceless, four-faced opalescent glass clock. (Another of its faces was later pierced by a bullet—apparently fired by a police officer in pursuit; that face is now at the Transit Museum.) More recently, Act Up and Occupy Wall Street have also staged demonstrations there.

Grand Central became the shelter of last resort—a terminal in every sense—for the homeless, whose encampments dotted the yards and tunnels beneath the streets and the terminal’s public spaces. In Subways Are for Sleeping, Edmund G. Love wrote that Henry Shelby, a vagrant in 1953, would hunker down on the benches at Grand Central, where he could sleep prone and undisturbed for four hours between the regular police checks at 1:30 and 5:30 a.m. Shelby kept a ticket to Poughkeepsie in his pocket as insurance, so he could always claim he missed the last train. “On one occasion,” Love wrote, “a station policeman escorted him to a 6:30 train and made certain he got on it. Shelby got off at 125th Street and walked back to Grand Central.”