Just a few minutes outside Manhattan lie the ruins of the future.

Millions came here 60 years ago this summer to see the "World of Tomorrow" at the 1939 New York World's Fair. Millions returned to the same spot 35 years ago this summer for the 1964 World's Fair.

But while the two events still have a claim on the American imagination, both actually failed in their central purpose, which was to leave behind a huge park on the site in Flushing Meadows, Queens. In fact, both fairs lost millions of dollars, and the would-be park was left to languish, littered with abandoned pavilions, sculptures, fountains and other fantastic structures that no one ever bothered to demolish.

Now, after seven years of renovations by the city, the Flushing Meadows park foreseen in 1939 has finally emerged, and many of the buildings left behind have been restored. The fairs are back, at least in part, saved less by intention than by fortuitous neglect.

Rocket ships and heliports, huge lighted fountains, amphitheaters and the famous abstract metal Unisphere shoot up weirdly from the Queens landscape. Crossing the original wooden boardwalk built to carry visitors from the elevated station over the Long Island Rail Road tracks, you can imagine the Trylon and Peri-sphere, the central symbol of the 1939 World's Fair, down the Avenue of Commerce and across the Court of Nations, and envision weary homebound fairgoers wearing blue-and-white buttons reading: "I Have Seen the Future."

Near the middle of this reconstructed fairground is the New York City Building, the biggest original structure that remains from 1939. It has been made into a museum primarily devoted to the fairs, and underwent a $15 million renovation in 1994. There is a huge and entertaining collection of artifacts, among them many of the souvenirs and sanctioned products generated by these highly stylized, heavily merchandised expositions: World's Fair guidebooks, World's Fair flatware, World's Fair china, World's Fair board games, World's Fair pins and banners. Such memorabilia have become prized collectors' objects among the many people who remember or study the fairs. Last year the museum added scale models of 13 pavilions from the 1939 fair built by one such devotee, a Flushing man who roamed the grounds and collected bricks from structures that had been torn down.

The building's centerpiece, however, is the most significant exhibit to survive from the 1964 World's Fair: the Panorama of the City of New York, the largest architectural model ever built, which shows all five boroughs in a scale of one inch to 100 feet; the Empire State Building is 15 inches tall. The Panorama originally took more than 20 workers two years to build, with its 835,000 miniature buildings, 35 bridges and 2,500 lights. Since updated to reflect the modern city, it is displayed in a huge room wrapped in ramps that offer views from every side and different heights. Day changes to night every eight minutes, and tiny airplanes even take off and land at La Guardia Airport. In 1964, fairgoers waited as long as 90 minutes to step into "helicopters" that flew over this model on a track in the ceiling while commentator Lowell Thomas extolled the virtues of New York as the apex of civilization. There's an original helicopter car in the museum, too, but now there are no crowds to jostle for a place at the railing.

The fairground is a shrine not only to a place, but to a time--or, rather, times: two of the most decisive periods in the century now coming to an end, and how the people of those eras imagined we would live today.

Marvels such as television, FM radio, robots, color film, fluorescent lights and miracle materials such as nylon, rayon, cellophane and fiberglass were introduced at the 1939 fair. Streamlined industrial design was incorporated into the very architecture of the Art Deco buildings, with their rounded contours and smooth surfaces. Visitors stood in line for hours to take a trip to far-off 1960--a world beribboned with highways full of aerodynamic cars--in the General Motors Futurama. In the Westinghouse pavilion, Mrs. Modern, with her newfangled dishwasher, beat Mrs. Drudge in a dishwashing contest every hour on the hour. The fair preached optimism; science, people were encouraged to believe, would solve the many problems of the day. But by the time the fair closed, World War II had begun, and the Trylon and Perisphere were melted down to make bombs.

The 1964 fair was as gaudy as its predecessor had been elegant. Brightly hued and garish, it was meant to be a bulwark against the creeping cynicism of the '60s, but it wound up symbolizing much of what people were becoming cynical about. The big American companies that had exhibited their products at the 1939 fair were back, but poor management and bad design had by then begun to cost them their predominance. GM reprised its Futurama, this time showing soaring cities with huge parking garages and elevated highways. But by then America's reliance on the car was coming into question, as cities were becoming blighted rather than Utopian. Unwavering patriotism was giving way to racial protests and a rising tide of opposition to American involvement in the Vietnam War. A president had just been assassinated. Mrs. Modern had become a feminist. And rather than solving problems, new technology had brought pollution and radioactive and toxic waste, not to mention the persistent fear of nuclear annihilation.

The center of the 1964 fair was the Unisphere, just outside the New York City building, now the hub of the 31 acres of the park restored so far. Familiar to a whole new generation who saw it for the first time in the movie "Men in Black," it, too, has been polished to a shine. Seen in person, the 140-foot stylized representation of the Earth seems precariously balanced, all 300 tons of it, tipped at the same 23-degree angle as the planet and wrapped in stainless steel rings that represent the path of the few man-made satellites orbiting the globe in 1964. It seems all the more monumental--if not melancholy--now that you can ponder it without the distraction of the noise and throngs that once swarmed around it. The surrounding Fountain of the Continents has also been restored, and bright colored night lighting reintroduced. The Art Deco flagpoles just beyond the Unisphere date to 1939.

Fairgoers also flocked to see a whole crop of hulking rockets that had suddenly sprouted from the middle of Flushing Meadows; it was, after all, the dawn of the Space Age. Three of the big ships remain, a short walk from the New York City building, and are being restored: an authentic Titan II booster with its two-man Gemini capsule, an Atlas with its Mercury capsule, and a mock-up of the first stage of the giant Saturn V that would take man to the moon. All are on the grounds of the fair's original, downright otherworldly Hall of Education, where audiences watched full-size spacecraft rendezvous above their heads. That building, too, survives, and it is now the New York Hall of Science, which underwent a $13 million renovation in 1996 that preserved its undulating, textured walls in kitschy retro testimony to the '60s.

Many of the surviving modern sculptures from the 1964 fair also suggest man in flight, some more successfully than others. The 45-foot-high "Rocket Thrower," for example, by Donald De Lue, one of the largest bronze statues in the world, shows a male figure with rockets and stars who stands in what in '64 was called the Court of the Astronauts. A New York Times critic called the work "lamentable" and "an absurdity." More successful was the bronze piece "Freedom of the Human Spirit" by Marshall Fredericks, depicting human figures soaring free of Earth. Both are near the Unisphere.

The Jordanian Pavilion left behind its "Whispering Column of Jerash," from the Roman temple of Artemis. And on the site of the Vatican Pavilion is the Exedra, an inscribed stone bench to mark the place where Michelangelo's "Pieta" was seen by more than 27 million visitors who stood on a moving conveyor to see the sculpture through bulletproof plastic, with a backdrop of a tacky purple crucifix and a halo of blue lights.

The 500-seat Theaterama in the New York State Pavilion has become the Queens Theatre in the Park. The Terrace on the Park, an elevated platform used as a heliport and restaurant during the 1964 fair, is undergoing an $8 million face lift and is scheduled to reopen this summer as a steak house, with panoramic views of both the park and the Manhattan skyline.

New signposts and maps make it easy work to find these landmarks, and some are so tall you can easily see them from across the park. Pathways have been built along exactly the same street plan as the fairs'. Hundreds of trees and colorful flower beds have been planted, new benches and lighting installed, and restrooms upgraded and made accessible for the disabled. A huge mosaic piazza was completed last year at the entrance from the elevated No. 7 station that depicts the Trylon and Perisphere and other signature buildings, and the Fountain of the Fairs, between "The Rocket Thrower" and the Fountain of the Planets, is being rebuilt into one of the largest, most dramatic working fountains in New York. A $13 million renovation of the 28-acre Flushing Bay Promenade, which will include 1,266 shade and flowering trees and cast-iron benches that are replicas of those made for the 1939 World's Fair, is under way.

Something else was left behind in 1939 and 1964: two time capsules, each to remain unopened for 5,000 years, with messages from Thomas Mann and Albert Einstein, copies of Life magazine, a pack of Camel cigarettes, a dollar in change and other artifacts. Both are buried underneath a granite marker east of the New York City Building and the Unisphere.

"When we survey the past and note how perishable are all human things, we are moved to attempt the preservation of some of the world's present and intellectual symbols," the message in the capsules reads. "It would be pleasant to believe that we might leave records of our own day, to a day when the peoples of the world will think of us as standing at history's midpoint."

Jon Marcus is a senior editor at Boston magazine.

DETAILS: Flushing Meadows

GETTING THERE: From Manhattan, take the No. 7 Flushing subway to Willets Point/Shea Stadium. By car, take the Shea Stadium exit from the Grand Central Parkway.

BEING THERE: Flushing Meadows Corona Park, which is open daily, is quiet and uncrowded, except at the beginning of September during the U.S. Open tennis tournament. While there are no longer any grand international pavilions on the site, the friendly surrounding neighborhood has a distinctive Latin flavor and inexpensive ethnic restaurants.

Trolleys make a circuit of the subway station and park attractions from 10 a.m. to 6 p.m., Friday, Saturday and Sunday. The cost is $1 for unlimited one-day use. For information on the park, call 718-760-6565.

WHAT TO SEE: The original New York City Building, now the Queens Museum of Art, is open Wednesday through Friday, 10 a.m. to 5 p.m., and Saturday and Sunday, noon to 5 p.m. The suggested donation is $4 for adults, $2 for children. From 1946 until 1951, the building also served as the temporary headquarters of the United Nations; the state of Israel was voted into existence there in 1947. Some original antique World's Fair memorabilia that is not part of the collection is for sale in the gift shop. For information or group reservations, call 718-592-9700.

The New York Hall of Science, originally the Hall of Education at the 1964 World's Fair, is open Monday through Wednesday, 9:30 a.m. to 2 p.m., and Thursday through Sunday, 9:30 a.m. to 5 p.m., until June 30. Summer hours are Monday from 9:30 a.m. to 2 p.m. and Tuesday through Sunday 9:30 a.m. until 5 p.m. Call 718-699-0005.

--Jon Marcus

CAPTION: The Trylon and Perisphere stood center stage at the 1939 World's Fair in New York's Flushing Meadows. Today, though the '39 icons are long gone, the park is undergoing a revival.

CAPTION: The 300-ton Unisphere, shown here in 1964, is still the centerpiece of Flushing Meadows Corona Park.

CAPTION: Above, a detail from the updated Panorama of the City of New York, a mammouth architectural model built for the '64 fair. At left, a sign touting the earlier event.