At 05.45 hours in Seoul, the weather is vile. Wild, windy and dark as sin, the bleakness of the city seems fitting for a visit to the last frozen pocket of the Cold War, the ironically titled Demilitarised Zone. I shiver as I think of what’s ahead – a visit to the most heavily fortified area on earth, the flashpoint where tensions have been running high this year, most recently resulting in the shelling of Yeonpyeong Island and the deaths of four people.

The strip between North and South Korea, the DMZ runs the entire 250 kilometres of the Korean peninsula, marking precisely where the Korean War ended in an uneasy ceasefire 57 years ago.

Pushing my nerves aside, I hurry on. I’m expected at Seoul’s US Army base, Camp Kim, at 0700 hours precisely, and a lifetime of American military movies has drilled it into me that to be late is to be yelled at. I arrive with three minutes to spare, and relief washes over me. The building is filled with Americana: comfortable mumsy sofas, Christmas trees, and signed photos of cheerleaders. A gaggle of Europeans and Americans have straggled in from the cold, and, yawning, we are gently herded onto warm buses. Outside, a board lists US military camps around South Korea.

Next to the camps are the conditions: “Road closures”, reads one line. “Demonstrations expected,” reads another.

In front of me, two Korean-Americans start talking. “My grandmother had family in North Korea when the war happened,” says one, quietly. A meditative silence follows, before the second offers a very American response: “That sucks, man”. The first nods slowly. “They don’t even know she’s dead.”

A chirpy woman with Thatcheresque hair introduces herself as our tour guide, Jean. Looking down at her list of tourists, she says “You are all from countries that sent soldiers to the Korean War. Thank you.” As she begins talking about a long list of border skirmishes with North Korea, I think about the Hermit Kingdom. Kept afloat by Chinese trade and aid, the renegade state broods only 80km from the vast sprawl of Seoul, home to about half of Korea’s 48 million people.

For South Koreans, a visit to the DMZ is a visit to a near-mythical place, where relatives may still live out their lives unknown. For tourists like me, it’s a chance to see the last front line between 20th century ideologies, seemingly frozen in time and space, the last physical barrier between capitalism and communism.

As we pass the mouth of the broad Han River, I spy the border for the first time. I’ve never seen an armed border before, and the river is my first glimpse. I can dimly see small buildings across the river, scattered haphazardly on the small mountain range. To defend against any river incursion, razor wire and guardposts run along the entirety of the border, mere metres from the freeway.

I wonder at the temptation to defect for North Koreans living so near the border. The famine in the 1990s killed at least two million people — imagine seeing the pulsing glow of Seoul in the far distance, thinking longingly about food, so near, just across the river, but so, so far.

The freeway itself has defences – cinderblock firing points and large yellow barrels studded with sharp spikes sit next to the road, ready to be rolled in the way of oncoming armoured cars. We approach the civilian control line, and I notice that other traffic has dropped to nothing. It’s only our convoy of two buses. As we approach the bridge over the river Han, Jean tells us that we’re entering the first no-photo zone, 10 km from Panmunjon, the border village. Khaki clad soldiers wave us through, and the buses drive onto the bridge. There are barriers every twenty metres or so, forcing the driver to weave slowly through them.

As we exit the bridge, signs warn of antipersonnel mines. Large white cranes float by in a stately formation, flapping southward from the de-facto national park that is the DMZ. Four kilometres wide and stretching the entire 250 km of the Military Demarcation Line, the DMZ has been untouched by man since 1953, creating a haven for wildlife lucky enough to avoid treading on a mine. Rarities abound, including the nearly extinct red-crowned crane, the rare Goral sheep, Eurasian lynx, the last few Korean tigers, deer, Amur leopard, and Asiatic black bear. Like Chernobyl, places humans have rendered uninhabitable for ourselves have been a blessing for rare wildlife has flourished in the absence of humans. The cranes land and begin picking through fallow rice paddies.

We arrive in Panmunjon and our bus is boarded by a broad-shouldered US soldier, his black armband announcing he is part of the Joint Security Area forces. From the window of the bus, I can see a sign: IN FRONT OF THEM ALL, plastered across an elevated water tank. “If you’d all kindly follow me to a military bus,” says the soldier, Sergeant Juarez. The bus takes off, and the sergeant points out the elements of the DMZ’s defences. “The first part is an antitank barrier. The second is a minefield, and the third is a razor wire and chain link fence with rocks painted red and white,” he says. “The rocks are a low tech way of telling us if the fence has been tampered with, when we go on our patrols.”

The minefield is the first I’ve seen. I squint at the passing reeds, trying to make out some sign that the earth is deadly here. The mining squads have done their jobs well and there is nothing manmade to be seen aboveground.

The bus roars past well-tended rice paddies, with signs warning of minefields on the surrounding hillsides. “Freedom Village,” Juarez says, in his clipped military speak. “They pay no federal tax and there’s no military draft. But they have to be indoors by nightfall, and must bolt their doors and windows by midnight. We provide security while they farm. No men can marry into the village, but women can marry in.

Out the window is a denuded hilltop with a military post atop it. “That’s Observation Post OPLO,” he says. “It’s the last one manned by UN soldiers. From there, we can see 27 kilometres into North Korean territory.” Round the next corner, an immense South Korean flag towers above us. We pass a small barracks. “That’s our rapid response unit. They can be in uniform, in their trucks and in the JSA within 60 to 90 seconds.

Of course, the record is 45 seconds, and that was set in 1994,” he says, betraying the glint of a smile. Round one more corner and in the distance, an even larger flag stands atop an impossibly slender pole, North Korea’s blue and red just visible.

As we roll into the Joint Security Area, the first thing I notice is that it’s immaculately kept. The shrubs are trimmed, ornaments polished and statues pristine. There’s a soaring white building, Freedom House, in front of us, Built in 1985 to host peace talks, the building was never used, because North Korea’s leaders refused to cross the Armistice Line. Led into the building as two obedient groups, my busload follows the chatty Juarez through the echoing building out to the Truce Village.

“Before we enter this area, I must tell you that pointing, waving or any other gesture to the North Korean side will not be permitted,” Juarez says, his normal grin absent. “They will think you are trying to communicate, and it could provoke them. There are cameras and microphones everywhere, recording you.” Dozens of cameras bristle from the South Korean side, aimed at a low series of blue buildings – the decades-old Temporary Buildings with the border runs directly through the middle of them.

Humourless South Korean soldiers hold themselves at rigid attention, facing into the building. Two stand in the open space between buildings, facing up to a grey Stalinist masterpiece in three storeys, brooding over the area. All concrete and pillars and curtained windows, the only colour in the North Korean side is the single soldier, his chest weighed down with red blue and gold medals against his grey uniform.

Pointing at a smaller building to the right festooned with cameras, Juarez grins widely. “We’ve nicknamed that the Monkey House,” he says. “When groups of North Koreans soldiers arrive, they gesture at us.” An American tourist asks what gestures they make. Juarez runs his finger slowly across his wide throat. “That. Or they give us the finger,” he says. He indicates the Stalinist building with his head. “Behind those curtains are many cameras. They keep track of our comings and goings, just as we do theirs. Last year, there were 19,057 visits here by North Korean officers and soldiers.”

The middle building is where the meetings have taken place. The border that cost more than two million lives is outlined here by a small dark concrete line, barely a centimetre above the ground. This is the only place along the entire DMZ where North and South face each other without the four kilometre buffer of the DMZ. The North is barely putting on a show today.

One tourist raises his hand to ask a question. “I will say it again, because nobody is listening,” Juarez says sternly. “No gestures.” The man shrivels a little. “You will notice the North Korean main building has three storeys,” Juarez says. “They added a third storey after Freedom House was built, to make it taller than South Korea’s building. South Korea added height until they were exactly the same.”

Escorting us inside, the sergeant asks us to form two lines. Clearly, no-one here has done time in the military. Our two lines sway and disintegrate within minutes, drawn by the photo op of a stony-faced ROK (Republic of Korea) soldier. Juarez tsk-tsks at us but doesn’t deliver the drill sergeant routine I was secretly hoping for. As we board the buses back to Panmunjon, Juarez tells us that the road we’re on is the old highway that used to run from Seoul to Pyongyang, pre-war. The railway has recently been reopened, and carries goods from the joint-venture industrial complex a few kilometres over the border, where South Korean capital meets North Korean cheap labour.

Juarez bids us farewell and Jean takes control. We’re off to the Third Invasion Tunnel. “In 1974, we suspected something was happening,” she says. “There were odd noises and then a defector told us where to find the tunnel we thought was there. We sunk 100 bores and filled them with water. One day, the water disappeared in a bore and we drilled down to find this tunnel in 1978. It is wide enough to have let 30,000 soldiers through in a single hour” Incredibly, the North Koreans had drilled 1.7 kilometres through solid granite, 73 metres underground, using dynamite to advance metre by metre.

The Third Tunnel is remarkably steep. You enter a South Korean access tunnel, drilled steeply downwards to encounter the North Korean tunnel just where it stopped. The tunnel itself drips constantly, seeping through the granite. Dynamite holes are painted in yellow, to provide us with proof of North Korean doings. Helmets are mandatory protection against the low ceiling. Every few seconds, someone clangs their head. The tunnel terminates at a steel barrier with an embedded camera, beyond which is a minefield, and beyond that, yet another metres-thick barrier.

Jean told us Kim Il Sung got the tunnelling idea from the Viet Cong, and that the military estimate about 70 per cent of the North’s military hardware is hidden in tunnels. She tells us that at least ten other tunnels are believed to exist, undiscovered. This one is the closest, a mere 44 kilometres from Seoul’s teeming 24.5 million people. As we emerge up the steep incline, sweating and puffing, the buses are waiting to whisk us to lunch. We pass Dorasan Station, a gleaming white edifice with no-one in it. Three trainloads of tourists use it each day, but its main purpose – to once again link North and South Korea – has yet to be fulfilled.

Driving past forested minefields, we enter the Observatory under watchful military eyes. It’s now well below freezing and snow is falling. From atop the mountain, we can see deep into North Korean territory. Austerely beautiful mountains lord it over a scattering of small single-storey buildings and a single large factory. A blue-roofed village is visible to the right, with the flag towering over it and a single black skyscraper brooding in its midst. Jean points to a black tower, visible in the far distance atop a mountain. “They keep their people deaf and dumb,” she says. “That’s a jamming tower to stop any foreign radio or TV coming in.”

The village forms part of the industrial complex of Kaesong, where 40,000 North Koreans make women’s clothing for South Korean companies. To have the chance to work there, you must complete your long years of military service (ten for men, seven for women). They get paid about $60 a month by South Korean companies. The government taxes that down to $5 a month. But that’s still twice what the average wage is,” he says.

Outside, we peer through telescopes, squinting to see any sign of life. Flurries of snow spiral through the air, but on the ground, nothing moves. The Bridge of No Return – where POWs had to irrevocably choose their side and families were split forever – is starkly white amidst the brown winter landscape, not yet covered in snow.