The first day we took a tour to the Demilitarized Zone, that is the area along the border with North Korea, stretching approximately 2km on either side. No idea why they call it "demilitarized" when it is clearly packed full of firepower on both sides.
First stop on the tour was at a kind of visitor centre with lots of interesting artifacts kicking around, including this bridge, which had a wall at the far end symbolizing the closed border with the North, which was adorned with messages of hope from those people on the South side who had relatives in the North.
This bullet-riddled train was destroyed when the train line between the North and the South was bombed during the war. This train has been left as a monument to that time.
Near the train above, this bridge is known as the Freedom Bridge, and is part of the train line between the North and the South.
This is the last train station on the South Korean side of the border that is still in use. Note the sign to Pyongyang. Hopefully one day you'll be able to take a train from one capital city to the other.
This viewing point is just a kilometer or so from the border. Those hills you can see in the distance are actually in North Korea. However, you weren't allowed to take photos any closer than this. There was a line painted on the floor. However, you were allowed to look through the viewing machines. There wasn't a lot to see, though, except a few hills and some buildings that might have been factories in the distance.
This is the Joint Security Area, originally a village called Panmunjeom, on the actual border. The blue huts actually straddle the border and are used for negotiations. The soldiers in the middle are South Koreans, and stand in a kind of Taekwondo pose, some of them partially hidden behind the huts, as a defensive technique, so our guide said. The soldiers at the front of the picture are from the UN, and appeared decidedly more relaxed. The building in the background is in North Korea, and when we visited there was one guard outside. Occasionally you can see North Korean tour groups on that side too.
The whole area was very tense, with our guides very strict on us walking in two rows, only taking pictures where they said, and not looking back when we left. How much of it was necessary, and how much of it was for show, I couldn't tell.
Inside the middle of the negotiation rooms seen above, here I am on the North Korean side of the border, marked by a strip of concrete.
This monument harks back to an incident in the mid-70s when the area of Panmunjom was actually open and both groups of soldiers could walk around freely. Two US soldiers went to supervise the cutting down of a tree that was obstructing the view from one checkpoint to another. A group of North Korean soldiers appeared and the two Americans were axed to death. After the incident the border was set down and neither side was allowed to cross it. This monument is at the site of the tree. You can read a better account of the incident here.
This bridge, not far from the monument above, crosses the border, and is known as the Bridge of No Return. At the far end is a wall now, but at the end of the Korean War several thousand POWs from both sides were brought here and told to cross the bridge to the Korean they wanted to live in. Once their choice was made, there was no turning back, hence the name. Incidentally, only about 1/6 people chose to go to the North Korean side.