Major fighting between North and South Korea ended in 1953, when an armistice was signed. The agreement created the Korean demilitarized zone but there was no official peace treaty. Which means the Korean War never ended. For 64 years, the two countries have been separated by a narrow and heavily armed divide. We found both North and South, including over 37 thousand American troops, prepared to take up the battle again at any moment.
To arrive at the tensest border on the planet, we drove north drove 35 miles from South Korea's capital of Seoul. Barbed wire and guard towers appear among lush fields of rice before we hit the first checkpoint.
Security is serious because the two countries don't recognize each other as sovereign nations. They're still officially at war. Once on site at the demilitarized zone, or DMZ, we can look over the mountainous green landscape into North Korea.
Harold Raugh: The DMZ is not demilitarized, it's probably one of the most militarized spots on Earth, with a number of divisions and hundreds of thousands of soldiers and hundreds of artillery pieces of both the ROK army, the Republic of Korea army, and the North Korean army facing each other.
Harold Raugh is a military historian assigned here with the combined U.S. South Korea forces. What is this music we hear?
Harold Raugh: This is really propaganda. Both sides use multiple platforms to get their word to the other side.
Jeffery Lee: The Korean Flag sticking up, that is the last village before, you can, you get straight into North Korea.
Captain Jeffrey Lee is among the 37,000 U.S. troops stationed in South Korea, more than half here on the front lines.
Sharyl Attkisson: Are you told to be poised for something to happen literally any second?
Jeffrey Lee: It's not that we're told, it's just that that's our mission every day. This is a picture of what we do on a daily basis. If you look at that concrete slab, that's the border, on the far side you have North Korean soldiers, here we've got U.S. soldiers and South Korean soldiers standing side-by-side. Really facing straight into the gut of the enemy.
Today, just like then, anyone trying to cross the border in either direction would likely be shot. The Korean conflict and the role the U.S. plays goes back to World War II. The Soviet Union and the U.S. drove out Japan and split the peninsula into the Communist North and the non-Communist South. In 1950, the North Koreans attacked the South. China backed North Korea and the U.S. aided the South. Over three years, 900,000 soldiers were killed, including 33,000 U.S. troops. An agreement signed in 1953 didn't end the war, but halted the fighting and established this 2 and a half mile wide demilitarized zone, or DMZ, on the border. The U.S. has kept troops here ever since. While North Korea has deteriorated under decades of Communist rule. South Korea has flourished, evolving from from a poverty-struck nation to a global symbol of economic success.
Tim Kane: No one would have predicted it in 1950, or even 1960, that South Korea would become one of the ten wealthiest economies in the world, and yet that's what we see today. And it's a democracy. And they protect human rights and civil rights.
Military analyst Tim Kane was stationed in South Korea his first assignment as a young Air Force Officer back in 1991.
Sharyl Attkisson: How important is the US, South Korea relationship?
Tim Kane: I characterize the U.S. South Korea relationship as the best U.S. relationship. Not the strongest, or the longest, or the deepest necessarily, but it really highlights what can happen with an alliance based on freedom.
The U.S. South Korea alliance appears more critical than ever amid North Korea's escalating rhetoric, but so far, the historic bonds are holding.
Tae Min Suh: There are many good relationship between Korea and the United States
Former South Korean Army Lieutenant Tae Min Suh suffered through the ravages of the war and its aftermath. That's him in middle talking with a US officer. Today, like many older Koreans, he still feels deep gratitude toward America.
Sharyl Attkisson: Can you tell me a little about the US relationship with Korea in 1950s and 1960s?
Tae Min Suh: At that time our country is very poor and not covered by a defense budget then we relied on US assistance, military assistance, as well as civilian assistance.
Without that U.S. assistance, many believe South Korea would have been overtaken by the Communist north.
Jeffery Lee: From a personal standpoint, it resonates with me a lot more, because as a Korean-American, my parents emigrated to the states in the 80s. If the U.S. hadn't intervened in the Korean conflict in 1950, I wouldn't be standing here wearing this uniform today. Standing in a U.S. army uniform on the border of North and South Korea. Defending, really freedom -on freedom's frontier- to defend against any aggression against the free world.