Here are a couple of photos from my trip to the Joint Security Area (JSA) last month.
The blue building on the left is the conference room where negotiations take place. The big building in the background is the North Korean base where running NK soldiers can be seen on this video
http://www.bbc.co.uk/news/av/world-asia-42075986/north-korea-defection-footage-of-moment-soldier-flees This took place around ten days after our visit.
The second photo is inside the conference room. The soldier is ROK (Republic of Korea = South Korea) and is stationed against the door through which North Koreans enter the room. He is there to resist any attempt by North Koreans to snatch visitors, as they have tried to do in the past.
The line across the table indicates the border between North and South Korea. We were able to step into North Korean territory in the room, so, by a couple of metres, I have added NK to my list of visited countries.