The modernist Marcel Duchamp once argued that America’s only contribution to art (aside from phenomenal plumbing) are her bridges. My four-year-old twins might agree. Like most toddlers, their passions are unpredictable and often fleeting. Yet, their enthusiasm never wanes for New York’s majestic bridges and endless tunnels. Even the tired old Whitestone, its sea-green towers begging for Rustoleum, still thrills them.So, inspired by the clamor that greeted the congested George Washington on a sunny and crisp afternoon last spring, I suggested we devote a day to nothing but bridges and tunnels. Upon reflection, I believe I was delirious from exhaust clogging the toll plaza. I forgot about it before we got home. My son and daughter, of course, did not. Any offer, however lightly or ambiguously made, is a promise taken, filed, and posted on the bulletin boards of their memories. I almost slipped into shock the following Saturday morning when four small hands pummeled me awake. “When are we going on the bridges?” they asked. “When? When?”

“Soon,” I mumbled, and pulled the blanket over my head.

Many families endure driving rather than enjoy it. New minivans are playrooms on wheels, fitted out with VCRs, refrigerators and MP3 players. “20 Questions” and coloring books have given way to Game Boys and movies, but the intent remains the same: keep the kids from rioting. My twins, on the other hand, adore the open road. Everything they see is fodder for their backseat dialogues, which plumb such mysteries as why there are so few purple cars, why Cruella de Vil never gets a ticket, and what Daddy means when he calls the guy in the next car an idiot.

After putting the kids to bed a few evenings later, I plopped down in front of a Yankees game with my atlas. I was surprised to count more than 80 bridges and tunnels crossing New York’s rivers and bays. I’m only planning a daytrip, so on what basis do I winnow down the list? Architectural merit? Engineering wizardry? Historical importance? Interesting considerations, but all secondary. I have no doubt that my twins, like Hemingway’s Santiago, want only the big ones. The longer, the higher, the deeper, the wider, the better.

So, like a bizarre amalgam of General Eisenhower and a summer-camp director, I plot our crossings, mindful of where we can find food, water and clean toilets. The logistics prove annoyingly difficult, even presuming that no one will be shooting at us. I fill a trash basket with itineraries that don’t quite work before settling on a route of 10 bridges and four tunnels. We will hit all five boroughs and New Jersey. And when to go? B movies depicting New York emptied by alien invasion spring to mind. I know they are always shot on Sunday mornings.

Examining my list, I realize that despite living in and around the city for 40 years, I know next to nothing about our destinations. A few hours surfing the web and reading Sharon Reier’s The Bridges of New York, flood me with engineering specs, bios of the egomaniacs who drove the projects, and the greasy political backdrop to much of the city’s big-ticket construction. Not only is my curiosity quenched, but also I feel armed for the thousand questions my kids are sure to pepper me with. (My son makes Tim Russert look like a Carthusian.)

I give the twins a week’s notice and say only a hurricane will stop us. I’m excited, and have no doubts they are too, if reminding me twice a day is any indication. But Friday night brings panic. Not for the kids, just me. While tollbooths dance in their heads, I suck down my second Corona. The fact that I have no idea how long the trip will take intrigued me at first, but now I worry whether I have the endurance to drive all day, largely in and out of Manhattan. (My wife carries the are-we-there-yet gene and made it clear from the get-go that I was on my own.) I feel better after making a list of places where we can break any monotony. Still, I’m convinced that either an ethnic-pride parade or a charity bikeathon will stop us cold. And what about construction? Is this the weekend emergency repairs will finally begin on New York’s crumbling infrastructure?

Sunday, the week before Memorial Day. Winter refused to die this year and we’ve barely put our wool sweaters away. But the morning is already hot and muggy, a dog day in May. I scarf down a bowl of cereal as I pack for the road. My kids rarely eat breakfast. In fact they barely eat at all. I’m not sure my son has ever ingested solid protein. His diet is 98-percent pasta, but he won’t touch it cold and seldom likes it in a restaurant. I fill a baggie with ruby-red chips (the only ones he’ll eat), plucked from a bag of gourmet junk food. My daughter has a food allergy, which makes eating out problematic. But her passion for peanut butter and jelly is endless. I cram a small cooler with juice, water and her crust-free sandwiches.

We pile into our station wagon at 8:30. My wife’s anxiety matches our exhilaration ounce for ounce, and she makes me promise three times the twins will be all right. Apparently she thinks I can fend for myself, since she seeks no assurances of my safety.

My kids are exceptionally close and rarely fight or raise their voices to each other. But lately I’ve seen cracks in this Era of Good Feelings. My wife, a psychologist, says darker days are inevitable, dropping names like Oedipus and Electra. But we’re off to a good start this morning, since the twins are calling each other Horace and Jasper, pet names they’ve adopted after watching 101 Dalmatians continuously the last six months.

Before I know it we’re speeding through the Bronx towards the Henry Hudson Bridge, the northernmost entry into Manhattan. This is our usual route into town and the kids long ago nicknamed it the Blue Bridge, since it is. I feel our adventure officially begins as we rumble over the potholed lower deck, prompting me to dip into my new storehouse of Bridgeiana. I casually mention that an Indian princess who lived on the Manhattan hillside had to be moved to make way for the bridge. My daughter looks disappointed when I admit I don’t know where she went. But, like an over-eager politician, I add that the Henry Hudson is the longest fixed steel arch in the world.

We are across Manhattan and half way over the Triboro Bridge to Queens before I explain what steel is, what an arch is, and that the bridge was never broken. After taking a swig of Poland Spring, I almost add that we are now passing over a stretch of water called Hell Gate. But I doubt I have the stamina to answer the questions this would raise.

A quick ride under the elevated subway and we’re on the Queensborough Bridge. “Eccch!” my daughter says, and I agree. Scott Fitzgerald may have rhapsodized about the view it offered of the city, but the Queensborough, better known as the 59^th Street Bridge, seems like a failed improvisation with an erector set. I tell her that not all bridges are beautiful.

“Why?” she asks, pushing her fine blond hair from her eyes.

I think for a moment. “Because maybe the most talented people don’t build them, or they run out of money.”

“Why?”

“That’s a good question,” I evade, noting instead that, “Simon and Garfunkel sang a song about this bridge.” I already know that the word Garfunkel will trigger 10 minutes of laughter.

It’s only 9:30. I decide to take a break because we’re making such good time. I don’t want the day to end before noon. We head downtown as planned, but then slip away from the East River and park in an open-air lot.

Standing on Fifth Avenue, I point at the Empire State Building and announce we’re going to the top. The kids barely nod. We ride the elevators to the 86^th floor, which is as high as we can go today. We push onto the crowded observation deck and I clear a spot along the north side for the twins to peer through the metal grating. I succumb to the splendor and could spend the morning gazing uptown, even through the August-like haze. “That’s Central Park,” I say, just as the kids turn away. “Look!” I insist, as my daughter slaps her brother on the shoulder. “You’re it, Jasper! Catch me,” she yells, though I collar her before she flees. I tell myself to lower my expectations while the twins coo over a display of giant pencils in the gift shop.

Back on the road, a few blocks from the Queens-Midtown Tunnel, I’m anxious to see my daughter’s reaction. Her enchantment with tunnels, I’m sure, has blossomed partly in response to my son’s early claim on bridges. In fact, the only tunnels she’s actually been through are highway underpasses. So this is like showing a whale to someone who’s only seen goldfish before. No matter that the tunnel is dim as a coal mine and just as filthy. “Tunnel!” she shouts as we fly through. Her sparkling eyes tell me that whatever she imagined the tunnel to be, it’s more.

The next hour passes too quickly. We ricochet across the Williamsburg, Manhattan and Brooklyn Bridges. Little over a mile separates the three at mid span. I want the twins to appreciate each bridge, but there is no place to park that I would feel comfortable taking them out. And, as a couple of drivers remind me with either their horns or middle fingers, light traffic is no excuse to slow down and smell the asphalt.

The kids don’t mind. The bridges accommodate strollers, bicycles and trains, as well as cars in lanes narrow as bowling alleys. (Keep your hands inside!) It’s a three-ring circus out there. And even at 40 miles per hour, the Brooklyn Bridge’s remarkable granite towers and harp-like web of cables make a deep impression. My daughter announces half way across that it is her favorite. My son, perhaps venting a nascent sibling rivalry, proclaims, “I like the Williams Bird the best.” I would correct him, but I like his name better.

I mention that the Brooklyn Bridge was built in 1883. Two blank stares tell me that the concept of “1883” is as meaningless as “1492” – or “1992.” No matter. I pass out sandwiches and chips as we glide into the Battery Tunnel for our final trip across the East River. “Tunnel!” my daughter proclaims, her ardor undiminished, and I say that, like them, I have never been in this tunnel. My son squints and accuses me of being a joker, our polite way of saying someone is lying. I reach back to brush some crumbs from his Bugs Bunny tank top and realize that apparently there’s nothing I haven’t already done. Perhaps I should take it as a compliment.

We emerge and hurtle down the highway to the big one, the Verrazano Narrows Bridge. The bridge is so long, I announce, that it is slightly arched to match the curvature of the Earth. Thankfully they don’t probe this point, but my son asks if this is an old bridge too. I say not nearly as old as the others, and that Daddy even remembers when it was built. “They brought in Indians to work on the towers,” I say, and then head off the inevitable ‘Why?’ “Because they weren’t afraid of heights…or something.”

I have been to England more often than Staten Island. I’m amazed when the Verrazano deposits us on a wide-laned expressway. We’re still making good time and I surprise the kids by zipping off the highway and navigating through a leafy neighborhood to the inconspicuous Staten Island Zoo. I don’t realize how sweltering it is until we’re out of the car. My daughter wilts as we cross the baking blacktop, but I know she will mutiny if I suggest we skip the animals. She perks up when I point out a sign for pony rides. But they tell us at the riding ring that the heat has forced the ponies inside on humanitarian grounds. I’d like to join them. Instead we wander through the cool but pungent monkey house. My daughter’s cheeks are still flushed and I carry her to the car. Could it be sunstroke? I’m a dead man driving if she’s sick. She drinks two boxes of apple juice. The AC blows a gale and I recall how Richard Nixon blamed his 1960 defeat on his promise to visit all 50 states. Why did I have to hit all five boroughs?

I have a choice now. Either head out to New Jersey or cross the harbor to Manhattan on the Staten Island Ferry. Jersey is farther but at least we’ll stay chilled. I haven’t mentioned the boat so the kids won’t be disappointed if we forego it. Frankly, it’s more for me. I’ve never been. My daughter looks refreshed and I decide to go. I can always turn around. Happily it’s a straight shot to the dock and a brief wait to board. The sun is brilliant, but the novelty of the ride, the sea breeze, and perhaps the juice restore us all. The men’s room on board makes the monkey house smell like a pine forest (I doubt Duchamp ever rode this ferry), but I insist we use it. I don’t know when we’ll see another. We don’t come as close to the Statue of Liberty as I would like. The twins are dancing like a couple of Brueghel peasants as we pass her.

Battery Park and the streets of lower Manhattan are jammed as we drive off the ferry. No alien invasion here. We have only two tunnels and two bridges left. But between the Verrazano, the zoo and the ferry, late morning has slipped into mid afternoon. It’s half past two, and Hudson Street, a few blocks south of the entrance to the Holland Tunnel, is clogged. We’re not moving and I can’t even see why, since a Daily News delivery truck blocks me. What’s more, I hear scuffling behind me and I sense that comity is breaking down. “He hit me,” my daughter yells. “I hate she!” my son screams back. I separate them and stuff Raffi into the tape player. As usual, he’s musical Xanex. I think about shaving the itinerary. I had planned to take the Holland to Jersey and swing right back through the Lincoln Tunnel before scooting up to the George Washington Bridge. It would be so much easier to head for the GW now.

What stops me, aside from a pigheaded desire to finish what I set out to do, is the notion that bypassing the tunnels will shortchange my daughter. So we fight our way inside and exchange the sunny afternoon for a fluorescent vapor. I click Raffi off. We vibrate instead to the tunnel’s own hum. What is it? The reverb of a thousand car engines? Or the drone of the hidden machinery that prevents us from choking on carbon monoxide? I’m surprised no one is asking, and I find two sedate faces in my rear-view mirror. I mention that this tunnel is famous for its ventilation system when my daughter interrupts me.

“Daddy, I want to ask you something.”

“Yes, sweetheart?” Once again I prepare to have the thin veneer of my knowledge ripped away. I can’t explain the ventilation system in my house, let alone here.

“Why does Ariel pull Eric out of the water?”

It takes me a moment to realize that she’s not asking about Clifford Holland and his ventilation system. She’s talking about The Little Mermaid.

“Because,” I say, “Eric is not a merman. He can’t breathe underwater. If Ariel doesn’t take him up, he’ll drown.”

“Oh,” she says. I look in her eyes for a clue as to why she is wondering about this now. Because we’re under the river? Is she frightened? I reach back and hold her hand.

I’ve had enough, too. Perhaps this is what a submarine is like. The bridges are a Carnival Cruise by comparison. Outside at last, I let go of my daughter’s hand and clip on my sunglasses to fight the glare. The line of cars spreads like a fan and it is bracing to move beyond second gear. I roll down my window to feel the wind on my face and I see myself like Tony Soprano: confident, riding high, king of the meadowlands. I’m singing. Woke up this morning, and got yourself a gun.

“What?” my son asks.

I’m about to explain that it’s only a song when I get a sour feeling that I’ve missed the right turn that was going to take us straight to the Lincoln Tunnel. What’s more, the road is hooking left. Before I can blink, we’re on the Jersey Turnpike Extension. I wouldn’t mind if we were Northbound, but I see the World Trade Center fading into the distance on my left, and I know we’re heading South. I say we’re lost and the kids erupt. My son wants to know precisely how and why. My daughter looks like she’d jump up and start a Conga line if she wasn’t belted in. “The Daddy’s lost,” she chants. “The Daddy’s lost!” I announce that I cannot answer any questions because I need to concentrate and I raise my right hand in the international sign of silence, which is completely ignored. “Why is Daddy yelling?” my son asks. I flip Raffi on again.

My neck tightens like a blood knot in the 45 minutes it takes us to reach the Lincoln Tunnel. I check out my daughter as the lanes converge. “You okay, honey?” I ask. She smiles through narrowed eyes. Weariness has overcome anxiety and excitement. My little boy yawns as we slide into the tunnel and I ask if maybe he feels like a nap. The mere suggestion is the equivalent of shocking him with a defibrillator. I pull Raffi from the tape player. We’ve sung “Baby Beluga” four times and my head will explode with one more chorus. I cut off the protests by explaining the expression, the light at the end of the tunnel. The battle to be the first to see the light keeps them quiet.

I thank God we’re finally out and moving up the West Side. We pass Intrepid, the Navy’s aircraft carrier museum. My brother has said it’s a fascinating place for kids. I want to tell the twins, but I’m concerned they’ll insist on going tomorrow. Traffic slows as we near the bridge exit, and I envy a sailboat outpacing us on the glimmering river. Le Corbusier called the GW the most beautiful bridge in the world. None of us seem to notice. My son’s only question as we cross is whether Pez is a dessert.

Our day will end with the Tappan Zee Bridge taking us back over the Hudson. The Tappan Zee, in fact, is the only bridge the kids specifically requested me to include. I told them a few months ago that the old span might be demolished to make way for a new one. They’ve asked many times since how it will be knocked down and what will happen to the wreckage. I know from bedtime reading that they are in thrall to tales of looming chaos. While they demand I read a favorite story about a gang of renegade sheep totaling a jeep, they also want the hall light on brighter afterwards. The prospect of the three-mile long Tappan Zee plunging into the water must be terrifying and terrific.

It’s five o’clock. A dark wedge of Canada geese honk overhead, probably calling it quits after devouring a nearby fairway. Thick gray clouds that threatened a thunderstorm have dispersed, revealing the high sun. It is certainly a few degrees cooler and perhaps the Staten Island ponies are out again. Standing atop the Empire State Building, I wouldn’t have dreamed we’d still be on the road this late. It’s not summer yet, but I sense we’re racing into one of those Sunday afternoon backups that stretches from the Tappan Zee toll plaza to the shuffleboard courts at Kutscher’s.

I feel I’ve got nothing to lose, so I exit the Palisades Parkway before it sweeps inland and dumps us onto the main bridge approach. Instead, I head up old Route 9W, through the towns of Palisades and Piermont and a few riverside hamlets. I’m praying we find an entrance to the bridge that skirts the traffic. Construction forces us onto a detour, and for a while I’m flying blind, not sure if we’re even going the right way anymore. I keep this to myself. I fight the urge to turn around and my gamble pays off. We reach the bridge and avoid the worst delays.

The half-hour ride home is a victory lap. “We did it!” I say, pumping my fist like Mark McGwire after ripping his 62^nd homer.

“What did we do?” my son asks.

My wife greets us in the driveway. She opens the door and the kids pull her inside. Their second wind has hit. “Mommy!” they scream.

I march behind the wagon to get some feeling back in my legs and stretch my back. The grass was cut while we were out and the scent is a tonic. A wild turkey is perched atop the swingset.

“Tell me all about it,” I hear my wife say when the twins finally release her. She unbelts them but they linger in their toddler seats. I peek at the back of their heads and think how sparse are my own memories of being four. I laugh when I recall locking my mother out of our Bronx apartment and gleefully tossing her shoes from the fifth-floor window. And I can still picture an afternoon drive to Long Island in our ’57 Buick Special to see our new house going up, my father barreling down the Southern State Parkway, a Camel squeezed between his fingers. Is he listening to Nat King Cole on the radio? Maybe. Perhaps I could recover more on the couch. But will my kids remember anything from our big day a year from now, let alone 40?

I’m listening, astounded at how precisely the twins tell their story. They skip nothing, jabbering back and forth like a pair of Eyewitness News anchors. I slip into the driver’s seat to hear my daughter describe the observation deck of the Empire State Building, including people she bumped into. My son names the color of every bridge. They recount the ferry in enough detail – spelling out the differences between the upper and lower decks – that I wonder if I was napping on board. Finally they outshout each other to reveal that we got lost in New Jersey.

“Really?” my wife asks, looking at me for confirmation.

I nod.

“Daddy was driving like a maniac!” my son says.

They’ll remember.