The boundary line between North Korean and South Korea is the Military Demarcation Line, MDL. It bisects the peninsula east to west, except in the western portion, where it runs mostly north to south. Seoul is only 30 miles south of that portion of the MDL. The terrain on 2.5 kilometers on either side of the MDL constitutes the Demilitarized Zone.
Panmunjom village was located near what became the MDL during the Korean War. It was there that final negotiations between the US and its allies and the Chinese and North Koreans were held. Prisoners were also exchanged there upon the cease-fire agreement. That village had actually been destroyed in the war before the negotiations started. The place now called Panmunjom, above, is a wholly artificial construct designed for ongoing military-to-military contacts between the United Nations Command (meaning US/ROK) and N. Korea, officially known as the Democratic Peoples Republic of Korea.
Panmunjom actually straddles the MDL; it is free on one side and communist on the other. There are several buildings there, one of which is used for the meetings, which have continued fairly regularly for several decades. The negotiation table inside this building (more like a shed) sits exactly centered on the MDL:
One side of the table is in South Korea, the other side is in the North. When I visited there were no N. Koreans in the building, so we were allowed to walk around the table, thus technically entering North Korea, though obviously only by a few feet. Somewhere I have a photo of me standing on the Northern side of the table.
Panmunjom sits inside a four-kilometer-wide strip of the DMZ called the Joint Security Area. The JSA, including Panmunjom, is staffed on our side by a combined ROK/US detachment. The DPRK side is staffed by North Koreans, obviously. There is a low hill on the DPRK side of Panmunjom. Atop the hill the DPRK built a high and wide building, as you see in the first photo, above. It is meant to overawe us with its foreboding. It’s a joke because the whole building is really a façade that is only two meters (6-1/2 feet) from front to rear.
The 1953 Armistice established a Neutral Nations Supervisory Commission (NNSC) as an independent, fact-finding body for maintaining the armistice. Originally it was composed of senior officers from four noncombatant nations. We selected Sweden and Switzerland, the DPRK and China selected Czechoslovakia and Poland.
The Czech component was forced out by the DPRK early in 1993. The Polish component was forced out by the DPRK early in 1995. Note that those are the years those two nations shrugged off the last of their communist chains. The Swedish and Swiss delegations are still encamped in the southern half of the DMZ adjacent to the JSA. The former Polish and Czech camps are now used by the North Koreans for their own purposes.
I did not take these two photos; they are from Business Insider's photo-essay about the DMZ. It seems pretty much nothing has changed in the last 35 years.
Except for my trip to this site and a few trips I made (heavily armed) to the two US posts inside the DMZ, I spent my DMZ duty at what was then the only active firebase in the US Army, Firebase 4P1. I wrote about I wrote about that singular experience here.