Another few miles and Kwon points towards an industrial complex, the place where LG, the vast electronics company, is developing its "eighth generation" technology; so sharp and real, he jokes, that they don't dare bring it out for fear of people walking straight through the screens.
So far so good on Freedom Highway. But now, 24km in, the tone of our trip begins to change. Besides the billboards, we begin passing under several bridges daubed in cheaper fly posters. The bridges seem unnecessarily frequent and yet they carry neither traffic nor pedestrians.
Kwon's face becomes more sombre. They are anti-tank devices, he explains, dummy bridges, primed with explosives, ready to be detonated in the event of an invasion.
To the South Koreans, this is not idle talk: the Seoul subway has signs telling passengers what to do in an attack. Not a year goes by without some dangerous border skirmish or serious naval incident (such as the sinking of the warship Cheonan in March or the North's shelling of Yeonpyeong Island); they consider invasion a real and present danger.
Before World War II, Korea was a colony of Japan. When the Japanese surrendered to the Americans, Korea was freed but divided into two zones of occupation roughly along the 38th parallel: North-Soviet and South-American. Political chaos and infighting ensued. When the Korean War broke out in 1950, China backed the North Koreans with air support from Russia while America backed the South Koreans with the support of the UN, including New Zealand. Communism faced capitalism in what was effectively a cold-war super-power showdown by proxy. The ceasefire signed on July 27, 1953 was only an armistice agreement, and the two Koreas remain technically at war.
Forty kilometres out of central Seoul, the Han River is mingling with the murkier waters of the Imjin River, which the South Koreans call "the river of the dead" because of the number of bodies that (they claim) floated down from the North during the rumoured famines of the 1990s. It's a macabre name for a macabre place.
We begin to pass pillboxes, troops, sentry posts and artillery. Our journey slows. The last few kilometres are clogged with checkpoints, and both sides of the road have stark warning signs: "Danger of Death - Landmines". But the strangest thing of all is that when we arrive at the infamous Demilitarised Zone (DMZ) - "the scariest place on earth", as Bill Clinton once said - we find it is packed with giggling crocodiles of children in bright yellow tracksuits and coaches full of buoyant pensioners wearing visors and eating ice creams. And there's a funfair and candyfloss and fast-food restaurants and people selling baseball caps and yoyos, and somehow the whole thing is wrong.
The DMZ was originally created as a buffer zone. Running for 257km across the Korean peninsular, it is 4km wide - two on either side of the actual border - and the idea is that neither side deploys military hardware inside its confines. When you watch the video as part of the "DMZ experience", they make the case (after the scenes of orphans and slaughter) for it becoming a wonderful nature reserve. But the DMZ is no more the place for a funfair than a fairground is for testing missiles.
Putting aside the history of the actual war - families severed; three million slaughtered - there has been a steady recurrence of shootings, stand-offs, murders and maiming in and around the border every year since.
Perhaps the most chilling incident (and there are plenty of candidates) was the killing of two American officers by North Korean guards, who brutally hacked them to death with the axe they were using to trim a tree that obscured a line of sight in the Joint Security Area (JSA).
The JSA is the area right in the heart of the DMZ where the two sides meet to negotiate in the blue huts that straddle the actual border and are painstakingly divided with equal square footage, lines down the centre of the tables, same number of chairs, etc. The JSA is also where the guards of the two nations stand face to face, legs apart and fists clenched, quivering in readiness to fight, seize, repel or shoot defectors, one side wearing sunglasses so they don't get into any incendiary staring matches.
Ice creams and souvenirs notwithstanding, the main thing the visitor comes to feel when considering all this - the military machismo, the acronyms, the deadly infantile theatre of the guards, one flag higher, the other flag wider - is that the whole place is about as insane as humanity can manage: terrifying, ridiculous, brittle, fraught, psychotic.
So to the last part of our tour - the Third Tunnel of Aggression - in its way, the most sinister "attraction" of our day trip. While negotiating above ground, the North dug a series of secret tunnels under the DMZ to rush troops up behind enemy lines. These were only discovered after a defector revealed their existence. . So far the south has found four, but there are rumoured to be a further 20.
First we catch the funfair-style monorail ride straight down into the ground. Then we begin a long and stooping walk in single file that takes us right under the DMZ. Eventually, in the narrow and damp claustrophobia about 150m below the surface, we come to a point where the south has blocked the tunnel with coils of razor wire, concrete and a massively reinforced steel door locked with the world's heaviest padlock.
If ever there was a visual metaphor ...
Someone brave and wise and with a very big heart needs to find that key and stop the madness.
CHECKLIST
Getting there: Korean Air flies direct from Auckland to Seoul.
Further information: See the Korean National Tourism Organisation website at visitkorea.or.kr. New Zealanders can order a free guidebook to Korea via the website.
- OBSERVER