After years of roaming around New York, I have found a great underground art gallery, maybe the best and most extensive you'll ever see. Follow me, and I'll show you the way.

Go to 41st Street at Times Square. Walk into the subway station. Go through the turnstile and look to your left. Now, feast your eyes.

Hanging in the wall between the uptown and downtown trains is a shimmering glass mural of everyday people by the painter Jack Beal. Not far away in the same station, a joyful mosaic by Jacob Lawrence shows children playing, commuters traveling, artists doing their thing. The works, both by New York artists, capture the vibrant democratic spirit of great public art.

There's more, much more, like it below the streets of New York, and the price of admission is only $1.50 -- the cost of a subway token. It may be the best aesthetic deal in town.

Though few people realize it, a renaissance of mosaic art is taking place in New York's subway system. From Harlem to Chinatown, Queens to Brooklyn, the century-old system has dozens of new installations, some fanciful, some sober, many eye-poppingly beautiful.

Backed by millions of dollars in public funding, prominent artists such as Elizabeth Murray, Deborah Brown and Bing Lee have been working closely with artisans for several years to transform their paintings into permanent displays, one small piece of glass, or tessera, at a time. Combined with a huge number of tesserae used as embellishment at the system's creation, the subway network very likely has the largest collection of glass and ceramic mosaics in the United States.

There are giant coffee cups and shoes beneath Bloomingdale's on the East Side; cavorting whales at Houston Street; and scorpions, dinosaurs, hummingbirds and other beasts beneath the Museum of Natural History on the Upper West Side.

"They're spectacular works of art. They burst forth like light almost," said Sandra Bloodworth, director of the Metropolitan Transportation Authority's Arts for Transit program and an artist whose own work is installed in a Lower Manhattan station. "It's part of our entire vision for the subway system."

Helping to realize that vision is Steve Miotto, a tough-sounding craftsman from the Bronx who has shepherded many of the works from vision to installation. One of the nation's leading mosaicists, the 49-year-old Miotto has worked on projects all over the country. In Washington, he installed several of the works in the floors of Reagan National Airport. In New York, you'll see his name alongside at least 16 works that he helped fabricate and install.

Miotto is tall, with big shoulders and a gold earring in his left lobe. He speaks with a heavy New York accent that belies his enthusiasm for the nuances of art, craft and creativity. On one recent Saturday, he agreed to take me to some of his favorite stations, starting at the Museum of Natural History at 81st Street on the B and C lines.

As we descended into the station, near Central Park, we brushed by people in the busy, echoing corridors to gander at the critters embedded in the walls. Most of the people were so intent on getting somewhere that they didn't appear to have a clue about what they were passing. But then, that's New York.

I took my time at every step, bending over to inspect the giant brown, beige and white ants that seemed to be on a march. Farther along was a blue, green and gray eagle soaring on a background of white tiles, not far from a three-foot-wide butterfly. There are caterpillars and fish, sharks and frogs, snakes, bats and hyenas, all of which seem for a moment to come alive when an express train roars through the station.

Miotto's pride showed on his face, and for good reason. In some cases, he cut the tesserae by hand, the old-fashioned way, with a carbide-edged hammer. In others, he worked closely with artisans in northeastern Italy, who execute the designs by the Arts for Transit staff. Some of the pieces contain gold or silver covered by a thin slice of crystal.

But more mosaics awaited, so we jumped on the C train toward downtown, then switched to a No. 1 at 59th Street. Miotto talked about the images that came into view at stations on the way downtown, some of them his work.

"It's a nice feeling to do things and know when I'm not around people are going to see it," he said. "The subway is a great venue for work. So many people are going to see it. It's not New Yorkers only. It's people from all over the world."

At 50th Street, we hopped off to get a better view of "Alice the Way Out," a fanciful collection of pieces by Liliana Porter showing "Alice in Wonderland" characters in blue silhouette. Look closely at the black top hat and you'll see an array of shades that most commuters miss.

Down the line at Times Square, as we admired the large images of commuters and children at play by Beal and Lawrence, Miotto explained the labor that goes into getting thousands of pieces of flat glass in just the right place.

They're affixed first to paper, he said, then lifted and sealed into the wall. Some of the works are put together initially, per Miotto's strict instructions, in a workshop in Spilimbergo, Italy, where he studied the craft years ago. Others emerge from his studio north of Manhattan, where he works with artists to translate their paintings into glass and other materials. We could have contemplated them for hours (especially if you add in the Lichtenstein mural not far away), but there was still much to see.

Next stop: Houston Street, for a collection of mosaics by Brown called "Platform Diving." Miotto beamed as he looked at one of the works, depicting a man on a bench reading a newspaper with a whale looking over his shoulder. (It makes more sense in person than it sounds. It's certainly more humorous.)

Brown, another New York artist, later marveled when asked to recall the process of turning her painting into glass in shades of blues, greens and yellows. "You see him approach it like a palette," she said of Miotto. "He really takes over."

Miotto and I made our way up to the street for a lunch break, then walked across town to Canal Street to a stop on the R line that is as luscious in its own way as the Museum of Natural History stop on the B/C line.

Miotto pointed out the bands of ceramic tiles, just overhead, that identify the station. They extended as far down the platforms as you can see -- thousands of glossy cut tiles in a work by Lee called "Empress Voyage." The bands, some of the newest in the system, include bright blues, jade greens and some browns, all mixed together in a way that somehow works like no other I saw.

I found myself contemplating the "Canal St." sign itself: blues surrounded by rectangles of pinks, yellows and beiges. On either side hung Chinese characters crafted for the space by Lee and Miotto. I rubbed my hand over it in a way I never could have in a museum. Very satisfying.

Around the corner are some 200 square hand-painted tiles, each about 13 inches across, also designed by Lee. They show cryptic symbols in blue and, along with his mosaics, serve as a brilliant counterpoint to the otherwise grungy surroundings.

Our next ride came on the R line. We rumbled up the East Side to the Eighth Street station for a quick look at an unfinished installation by artist Tim Snell, a series of circles meant to be mosaic portholes with views of scenes from city parks, monuments and the like. Then we caught the W to a collection of imaginary characters in the walls that look like figures from an old cartoon, all done in golds and a rainbow of electric colors. I'm told the group of pieces by Mark Hadjipateras, called "City Dwellers," is meant to evoke three industries active in the area above the station: flowers, toys and gifts.

On the W again, we zoomed by a station with polar bears, a gold horse and other animals (it is beneath the city's zoo) before stopping at 59th Street, and one of the most elaborate pieces in the system. Miotto wound through several passageways before stepping into a large room at the intersection of the 4, 5 and N, R and W lines below Bloomingdale's.

It was "Blooming," Murray's extraordinary installation, a gift to the city. All around us spread perhaps a quarter-million tesserae across more than 2,000 square feet of wall space showing giant steaming coffee cups, blowing trees and the words "Conduct your blooming in the noise and whip of the whirlwind," a line from a poem by Gwendolyn Brooks. Miotto ran his hand across the colorful, bumpy surface of the piece that he and Murray had collaborated on.

Our tour was over. It had taken about three hours -- and we'd barely begun to see the extent of the new art.

"We don't copy the work. We re-create it in a different medium, and we capture the spirit," said Miotto, who proudly calls himself a craftsman, not an artist. "I love what I do."

So will you, if you check out New York's subway station art.

Robert O'Harrow Jr. is a reporter in The Post's New York bureau.

Manhattan subway art, from left: a mosaic at the Museum of Natural History stop; a work by Jacob Lawrence at 42nd; and one of 100 eyes at Chambers Street.Above, sisters play in front of Eric Pryor's stained-glass art at Franklin Avenue. Below, a performance artist adds to Dan Sinclair's metal piece at 42nd Street.