This is the most heavily militarized border in the world.
But these days, the DMZ, or the demilitarized zone, which divides North and South Korea is not just about security.
It's a tourist attraction, complete with T-shirts, souvenirs and even a theme park which busloads of curious visitors visit everyday.
(SOUNDBITE) (Korean) 17-YEAR-OLD SOUTH KOREAN STUDENT PARK KYUNG-DOO SAYING:
"When I learned we were going on a school trip (to the DMZ), the first thing I thought of was the serious relationship we have with North Korea. But now that I'm here and can hear the music blaring and see all the rides I'm surprised to see how different the atmosphere is from what I expected it to be. It's good for the tourists."
But despite the festive mood, tension is never far away. In September, South Korean guards shot and killed a man trying to cross the border to the North.
During the unease, earlier this year, the number of visitors to the DMZ dropped.