SEOUL, South Korea - I have made it a general rule in life to avoid eating anything that fights back. Nonetheless, here at Noryangjin fish market, the dish before me - fully alive only moments before - is still squirming.

"Chew vigorously," my friend Nick advises me, as I seize a particularly ambitious piece of sannakji - a freshly dismembered bit of raw octopus tentacle - between the metal blades of my chopsticks, dredge it through a small dish of sesame oil, and pop it, writhing, into my mouth.

"I mean, I like the flavor," he muses, as a peculiar sucking sensation takes hold of my tongue and cheek. "But it's the feeling of it gripping as it goes down that I've really come to love."

I shoot him a look and swallow hard, feeling the unmasticated suction cups working their way down my esophagus.

This is Seoul. The sprawling South Korean capital region, almost destroyed during the Korean War, now is home to nearly 25 million people, all living, working, and playing - as they have since the cease-fire that ended the conflict in 1953 - within artillery range of a volatile North Korea. Still, that hasn't stopped the city, dubbed "The Miracle on the Han River" for its meteoric rise from war-ravaged poverty to global business dominance, from thriving in the shadow of the gun.

Like my vigorous octopus snack, it's an offering you've probably heard little about, but one that holds more than its fair share of surprises.

If New York is the Big Apple, and Jakarta the Big Durian, then Seoul may appropriately be called the Big Kimchi Pot. Like the earthenware jars that families bury in the earth to ferment Korea's ubiquitous pickled cabbage mixture, the city is, figuratively speaking, still mostly underground.

Don't let the low profile fool you, however: Like those clay urns, Seoul has some serious magic percolating just beneath the surface.

It's late Friday night a week later in Hongdae, the bohemian neighborhood surrounding central Seoul's Hongik University, and the streets are awash with neon and pounding music. Twentysomething students and expats drift in and out of a dense network of bars and clubs, and in the concrete playground at Hongik Park, a group of street performers launch into a long-jam version of Bob Marley's "No Woman No Cry." From the rooftop of dark, funky Bar Da, a famous artists' hangout a short distance away, I sit and watch the crowds pouring through the nighttime streets.

"You know, when I first heard the new tourism slogan, I laughed," says my guide, Myeong-Hee Jeong, a sixth-generation Seoulite. "I thought, 'Dynamic Korea,' what is that? But now, more and more, I think that it makes sense - you come to Hongdae at midnight, and you can see it everywhere, this kind of energy."

Indeed, from this vantage, few words would seem more apt.

I follow Jeong back down to the street, past crowds in vinyl tent bars quaffing shots of soju, the local rice liquor. All around us, masses are flowing into clubs such as Noise Basement, M2, and FF, or eating barbecue from streetside braziers set in low metal tables.

The night wears on in an alcohol haze into the small hours - people stumbling out of karaoke parlors (called norebang) and snacking from countless open-air food stalls lining the avenue. Even at 4 a.m., the streets never seem to empty.

It may be that Seoul really is the city that never sleeps. But even in a metropolis whose famously overdriven work ethic is matched only by its ferocious entertainment culture, there's still more than ample opportunity to experience a softer side of things.

Take the jjimjilbang. Korea inherited the tradition of these public baths from the Japanese during their occupation in the first half of the 20th century. The country gained its independence in 1945, with the end of World War II, but the bathhouse tradition stuck. Today, there are hundreds of these inexpensive, sex-segregated spas scattered throughout the city, where friends, couples, and even families take a well-deserved break from the city's relentless pali-pali (hurry-hurry) culture.

"Yay! Jjimjilbang!" chirps Hye-Jin Lee, 26, in the lobby of Siloam Spa. Studying for her real estate license, she keeps an unforgiving schedule but finds time to visit the baths regularly. "I love it here. . . . the hot water, I feel like I'm tea! No matter what, I soak in the baths, and my stress just goes away."

At just 9,000 won (about $8) for an all-day pass, the spa is arguably one of the world's most affordable luxuries, an example of the kind of unique and unexpected find that makes the city so beguiling. It's a place to bathe, relax, read, or just take a nap on the deliciously heated ondol floors of the common lounges.

Some Westerners may be hesitant to go the full monty with a room full of strangers, but they needn't be. Downstairs in the blue-tiled men's bath, I'm effectively invisible as I ease myself into the 109-degree hot pool, fragrant with the herby scent of mugwort, a sign incongruously touting its healing properties for "a variety of gynecological diseases."

After a few minutes, I'm completely steamed, and I pad over to the cold pool to plunge headlong into the icy water, instantly releasing a euphoric rush of endorphins that expands through my body as I sit immersed to my neck. I skip the vigorous ministrations of the massage staff in the "Korean Buff" corner, scouring spa-goers raw with nubbly green mittens. Instead, I choose the salt sauna, scrubbing myself shiny and smooth in the heat with stinging handfuls of coarse salt.

Ninety minutes later, I emerge into the twilight of the city, as clean, and relaxed, as I've ever been. The fabulous Changdeokgung Palace, a UNESCO World Heritage Site, waits just a short taxi ride away, but as visitors quickly discover, there's much more to the city than big-ticket attractions.

Instead, I hop a train on the fantastically cheap and efficient subway system to the affluent Gangnam district south of the Han River, to grab an espresso in the city's newest "it" neighborhood.

Coffee Smith cafe on the tree-lined street of Garosu-gil is the picture of chic - an open, industrial floor plan with curves of gray concrete and distressed wood. It's the kind of place beautiful people in Seoul go to see and be seen: women with perfect cheekbones and knee-high leather boots over tights and short skirts; men in $500 suede jackets.

Still, the fascinating thing is how different it feels from an upscale neighborhood such as New York's Chelsea.

"If you want to see the here-and-now changing of modern Seoul, this is definitely the epicenter of it," writer and teacher Glenn Pihlak says as he sips a cup of dark roast. "It's got this refined European aesthetic that's not just the conspicuous consumption you see elsewhere in the city, and all the boutique shopping and dining you'd expect. But the cool thing about it is that it's still Seoul. It's so new it doesn't belong to anyone yet; it stays hip without being exclusive."

We walk into the pre-spring air of late February, where, in the warm light of boutiques and wine bars splashing onto the sidewalk, the trees - like the city as a whole - seem on the verge of blooming.

"What people don't understand is that Seoul is just a huge mosaic," Pihlak says as we walk. "It's not like Paris or New York, where there's a list of sights you have to see or you haven't really seen the city.

"Here, you can go out dancing until 6 a.m. every night and then hit the little neighborhood next to your hotel for amazing noodles right after the subway opens," he adds. "Or you can spend every day in the markets, or shopping in the luxury stores of Gangnam, or a million other things, and you haven't seen the city any less than someone who just sticks to the itinerary in their guidebook.

"It's a city that can be done in so many ways, a place that really hasn't been mapped out."

Seoul Searching

American, Asiana, Continental, Delta, United, and US Airways fly to Seoul from Philadelphia with one stop. The lowest recent round-trip fare was about $1,643.

More information

For information about Seoul and the Republic of Korea (South Korea), go to VisitKorea, the official website of the Korea Tourism Organization (