I'll post a few pics later, need to download them. The DMZ is definitely "weird" the more I think about it. The South tried to make some small steps to reunification a decade or more back, so they built an entire factory just into DPRK, you could see it from our viewing site. They had about 500 South Koreans go there for work and several thousand from the North providing cheap labor. The South provided electricity and water. It's a pretty large plant, now defunct of course. The power lines were cut.
The bus drop off area where you get tickets is like a tourist spot with probably 80 tour buses and the aforementioned small amusement park, restaurants, gift shops, etc. You wait there over an hour while your guide gets tickets (he takes your passport). Then your reboard the bus and transit several pretty serious looking check points. ROK MPs come on the bus and check everyone's passport several times. There is razor wire everywhere and the fences are marked with land mine warning signs.
We toured a cave built by the North a few years back, that was back breaking for me. Then the bus toils up a hill to an observation post with fence lines and razor wire but access for tourists where you can see into the north and the actual DMZ. I didn't notice a heavy military presence, mostly observation points, radar, and some United Nations Command folks with Hummers. If the North attacked, I think they'd punch through quickly up there, the response would come from further south, or is hidden effectively.
All this is about a one hour drive north from Seoul, and quite a few large apartment buildings are closer than that. The guide said land got cheaper as you go north. No kidding. The South built a four lane freeway that runs parallel to the DMZ. There isn't much traffic on it (!). South of the actual DMZ is a zone reserved for the military though there are some villages and farms inside it (where we had lunch). Inside the DMZ is "nothing", basically. It's a bout a 3 mile wide strip that is "demilitarized". On the southern side one can see a paved road and fence line, nothing obviously much deterrent to tanks.
The freeway bridges have explosive charges built into them, if something happened the bridges would be dropped. The area is hilly, but with a good bit of flat land suitable for armor, and some very good highways in the south. I know the 2nd Infantry Division is now based south of Seoul.
I was impressed with the RoK. If that country were united, I think they'd be a significant world player economically, and soon, akin to Germany. They built an impressive country from ruins in fairly short order. Japan, to me, seemed tired in comparison.
