I am not surprised to see the ribbons of razor wire, the rifle-clad soldiers, the concrete bunkers or chain-link fencing that seem to have no end.

I expect the passport check, the restriction on photography, the no-nonsense surveillance by guards in camouflage, the need to board a military-controlled shuttle bus for the final mile or two.

What astounds me, upon reaching our destination, is the festive atmosphere — amusement rides for children; cartoonish statues; and T-shirts, paperweights and other souvenirs for sale.

This is what I know of the DMZ that has separated North and South Korea since 1953. A part of it thrives as a major tourist attraction, merely 30 miles northwest of Seoul. Visitors arrive via private driver or tour bus; travelers at Incheon International with enough time between flights can arrange airport pickup.

I’ve devoured eel to oxtail, bongsan mask to fan dances, at Korea House — the best one-stop destination for a cultural introduction in this city of 12 million. I know to head to Insa-dong for antiques, to the Namdaemun and Dongdaemun markets for just about anything else.

I can study centuries of royal living at Gyeongbokgung Palace or visit the National Folk Museum for a primer on the history, diversity and methods of making kimchi (with eggplant, cabbage, sweet potato sprouts — you name it).

It’s all good, and authentically Korean, but no place matches the impact and ingenuity of a DMZ tour.

The tours began in the 1960s but have become remarkably more extensive since then. It’s no longer a matter of simply following the Han and Imjin rivers for a while, as the barbed wire does for the first one-third of the DMZ’s 155 miles. Expect to set aside at least five hours (including travel time) and hit four or five stops when touring the DMZ today.

An odd mix of whimsical carousels for children and the somber machinery of war fill Imjingak Park, where I encounter an adult rollerblade team in bright yellow uniforms, joking and lounging at the foot of a war memorial.

I jockey around them for a short hike onto the wooden Freedom Bridge, which long ago linked Imjingak and North Korea’s Mangbaedan. Now it is a bridge to nowhere, ending abruptly with fence links stuffed with scraps of cloth and paper — many containing written pleas for peace and unity, in multiple languages.

“We can go anywhere in the world, except North Korea,” our Seoul guide reminds us, with exasperation. His father still lives in North Korea. The last time humans crossed the Freedom Bridge, it was to exchange war prisoners.

I never see the actual demarcation line, because we don’t have time to stop at Panmunjeom, where the armistice agreement was signed to end the Korean War. The tour here includes the Joint Security Area, the only place where North and South Korea connect — and the line actually divides a conference table.

Elsewhere, the demarcation line is buffered by the DMZ, an area about a mile wide on each side and impenetrable. This no man’s land, by default, is teeming with myriad plant and wildlife species, thanks to the lack of human influence.

So one aftermath of war is a rich refuge for the natural world, although it seems gray and dreary on the day I visit. Every once in a while, a fisherman’s boat accidentally crosses into the DMZ, prompting more gunfire warnings than usual.

The closest our shuttle bus gets is inside the Civilian Control Zone, a buffer before the DMZ buffer, where about 7,000 people live. All are descendants of people who lived here before the war; many farm rice or ginseng.

I am given a choice of construction hats: yellow for walkers or white for tram riders. Either way, the Third Tunnel Tour turns into a dank, dark and steep dip into a one-mile infiltration tunnel discovered in 1978.

The ride down makes me feel like a coal miner, minus the grime. What takes less than five minutes seems an eternity because movement is slow, daylight disappears and confines are narrow. I exit the tram for the last 50 yards, for a hunched-over hike to a bolted and locked gate.

That’s it. The tunnel continues, but we don’t. Instead of riding my way out, I walk a modern and well-lit steep path. The short but aerobic workout would make even a marathon runner puff.

Although less than seven feet wide and high, the Third Tunnel would have been big enough to move 10,000 soldiers (with gear) per hour. That’s reportedly what North Korea intended to do, and this is just one of four tunnels confirmed to be under the DMZ. No other can be toured, for now.

Next stop: Dora Observatory, a platform atop Mount Dora, the only place for civilians to safely stare at North Korea and maybe see something. I dig for change to feed a pay-to-use telescope and squint to see people or buildings in Gaeseong, the second-largest North Korean city.

No dice. The air is too hazy or the telescope too weak. Zooming in with a camera lens won’t be an option; a thick, yellow line on the pavement shows us where photography ends. Soldiers are vigilant and vocal about enforcing the rule, even when the camera in question is a measly point-and-shoot.

Before returning to the cosmopolitan bustle of Seoul, our bus veers to Dorasan Station, less than 800 yards from the DMZ. The empty transportation hub, built in 2003, awaits reunification of the republics.

Until then, I am able to walk onto the barricaded, four-lane highway and gawk at the vacant toll booths. Unless it is a Sunday, I can get a Dorasan Station passport stamp, at the train transit building, but cannot travel north with it.

What seems like the “Twilight Zone” or a surreal novel setting could change in a near-instant, should North and South Korea ever decide to physically reconnect. When or if that happens, it’s bound to present even more unorthodox tourist opportunities in Korea.