Our kayak rises, hangs in the air, then slaps back down on the water. Over and over again.

I want to admire the immense sandstone rock formations that rise out of the chocolaty water, but with these rough waves, staying upright demands all my attention. Then our guide leads the way into a quiet cove. The water smooths out. I put down my paddle.

Finally, I regard the curving reddish-brown rock that looms before us. The bulbous mass perches on two stocky legs, the hollow in its midsection carved by centuries of relentless water flow. Scraggly trees cluster on its topside.

I fish in the dry bag for my camera so I can take a picture of the giant, dubbed Lover's Arch, but our guide motions us on. The clock is ticking, and every minute counts.

We're paddling in the Bay of Fundy, home to the world's largest tides. In this finger of water tucked between the Canadian provinces of New Brunswick and Nova Scotia, water can rise and fall as much as five stories in six hours — a notion I found so preposterous that the only way to truly comprehend it was to see it myself. My husband, Ed, and I decided to do just that this summer.

Our adventure had begun an hour earlier, when we'd arrived at Baymount Outdoor Adventures, a New Brunswick outfitter that offers guided kayak tours of the bay. A clerk quizzed us about our paddling experience; we assured her that we'd kayaked before.

"Good," she said, noting the water was rough. "We're having 3-, 4- and possibly even 5-foot waves. You'll definitely get soaked, and there's the slight possibility of flipping."

Ed and I glanced at each other. It's true we have paddling experience — on sedate rivers and calm lakes. We've never battled roiling waves. But we were determined to experience the Bay of Fundy's tides while on the water, so we kept quiet.

A few paddling newbies were turned away — a blogger from Paris, a family from India, an elderly woman. Those of us who made the cut were handed paddles, life vests and spray skirts, then marched down to the beach and our kayaks. Now here we are, battling not just rough seas, but a tide beating a hasty retreat back to sea.

World's highest tides

To understand how Bay of Fundy's tides work, I looked at the numbers. About 160 billion tons of seawater flow in and out of the bay during one tide cycle — more than the flow of all of the world's freshwater rivers combined. While that's a colossal amount of water, it wouldn't necessarily equate into insanely high tides if it weren't for Fundy's shape. The mouth of the bay stretches 62 miles wide and plunges 400 to 700 feet deep. But at its northern tip near the New Brunswick city of Moncton, some 180 miles up the coast, it's a mere 2½ miles wide with a depth of 40 feet.

"When the tide comes in, [all the water is] squeezed from the sides and bottom," explains Jon Michael Keir- stead, an interpreter at the Hopewell Rocks provincial park, home base for Baymount Outdoor Adventures. "It has nowhere to go but up." Which is why tides can rise and fall as much as 53 feet. The world's average tidal range? A paltry 3 feet.

In this tip-of-the-funnel end of the bay, not only are the tides the highest of the high, but they're the most fleeting. Keirstead says high tide here lasts 30 seconds or so before the water begins to flow out again, falling an incredible foot every eight minutes until low tide occurs some six hours later. "It's a pretty massive change."

And one that people love to witness. Our itinerary is a popular one: kayak a few hours at the Hopewell Rocks, famed for its impressive sandstone formations, chiseled away from the cliffs by the tides, then return about 90 minutes later to stroll along the ocean floor. Exactly where we'd kayaked.

On the water, our guide leads us into another cove, teaching us about the bay and its tides. Even in this cove, the waves toss our kayak around like a cracker, so I can't concentrate too much on the commentary. But I do learn the basics: The tide goes in and out twice a day, the times for high and low tides move ahead about an hour every day, and full and new moons make the tides deeper.

Back on shore a few hours later, Ed and I admit we didn't notice the water level dropping as we paddled along. Would all of these still-roaring waves really be gone in a little over an hour? We walk back to our car, change into dry clothes and browse through some educational displays.

Soon our feet clatter on the metal steps leading down to Staircase Cove, home of the Lover's Arch formation. Hopping off the final step, we abruptly stop and gape. Just as promised, all of the water we'd so recently been battling is gone. There's no splashing surf, no swelling waves, no brisk winds. Just a wide expanse of soft, mocha-colored sand festively adorned with glistening strands of seaweed.

Groups of visitors wander about, seeing how far they can venture from shore before the mucky sea floor grabs hold of their feet. Others creatively pose by some of the more tide-worn sandstone pillars. A few simply watch the water recede farther and farther out to sea.

"Remember paddling through Lover's Arch?" I ask Ed, gently touching the sandstone walls of the arc.

I'd so recently worried that the waves would shove our kayak into this jagged rock, but now it appears picturesque and harmless. The sandstone down here where we're standing is about 13 feet below the spot where we'd kayaked, and is stained a black tea color from its frequent underwater submersions. That same black-tea mark is tattooed everywhere: on the cliff side, on sandstone formations, on tree trunks growing a little too low. It's tidal graffiti, creative and beautiful, yet a bit ominous. We explore the cove and then head back to our car. Who knows how soon the water will begin flowing in again.

Other vantage points

Over the next few days we drive down the coast and watch the bay widen and deepen and the tidal changes drop. In Alma, a waitress says the tides here reach 30 feet; in St. John we're told they're 25. Maybe locals can tell the difference between 50-, 30- and 25-foot tidal changes, but to us they're all tremendous.

We hike along trails in Fundy National Park and the Fundy Trail Parkway and explore beach after beach when the tide is out. All seem to sport a slice of dun-colored sand — the beach — that transitions into a sprawling expanse of seafloor. Sometimes we crunch along an ocean bed of small, gray stones; other times we're treading along coffee-colored mud that constantly shifts beneath our feet. Seaweed is everywhere, carelessly tossed aside in hay-bale-sized mounds or delicately laid out in single strands.

The Fundy Isles dot the mouth of the bay. A group of two dozen islands clustered along New Brunswick's southern coast and Maine's northern, the largest is Grand Manan, followed by Campobello Island, where President Franklin Roosevelt once had a summer home, and Deer Island.

We ferry over to Deer Island for another kayak trip, this time with Seascape Kayak Tours. Guy Quinn, our guide, says things are peaceful here — it's definitely not a tourist hot spot. Residents fish for a living, mainly trapping lobster, and the tide is around 20 feet. As we paddle out into calm waters, a bevy of wildlife quickly surrounds us: bald eagles, seals, cormorants, ducks. Although visitors love being able to see so many birds and animals when they're kayaking, Quinn says they're most impressed by the water movement. It's easy to see why when we stop for lunch on a tiny beach.

Herring nets

As Quinn begins setting up our picnic, he points to a series of wooden stakes poking up out of the water in a semicircle of sorts, just off the beach. A thick rope links the stakes. That's a herring weir, he says, an old but effective way of snagging the tiny fish. When in use, nets would be connected to the rope. We can easily see the stakes and the rope as we nibble on smoked salmon and fresh fruit. But as we eat, and the tide silently marches in, the stakes appear to be sinking into the water. By the time we paddle out an hour later, the roping is totally submerged and the stakes appear to be headed to the same watery grave.

I'm still marveling at the tide's quick appearances and disappearances the next day when I duck into Grand Manan's Island Arts Café. Local celebrity and centenarian Oliver "Smiles" Green is there, holding court. Green, I'm told, knows everything about the bay and its tides. I tell him he's lucky to live in such an amazing place, and ask if he finds the tides as fascinating as I do. He looks at me with amusement. "The tide has been the same for 100 years, as long as I can remember," he says. "We're used to it here. We don't pay no attention to it."

Seeing my disappointed look, Green recalls how his wife's grandmother moved to Grand Manan from England when she was rather elderly. She was immediately captivated by the tides, spending much of her time simply watching them.

"She'd say to us, 'But where does the water go?' " Green says. " 'Where can all that water possibly go?' "

Writer Melanie Radzicki McManus focuses on health and travel. She lives in Sun Prairie, Wis.