Politics and travel often don't mix. Many potentially interesting areas of the world are foreclosed to U.S. tourists by bad political vibes or worse: Lebanon, Cuba, Iraq. The borderlands where conflicting ideologies face each other are often tense and dangerous places. Eventually, however, some of these points of confrontation become quasi tourist attractions in their own right, peepholes into alien, if not enemy, territory. Checkpoint Charlie at the Berlin Wall was one such for years. The bridge between Hong Kong and the People's Republic, too. The Allenby Bridge between Jordan and Israel. In their time, all of these were enhanced as travel experiences by the hint of danger.

One enduring point of bitter, guns-loaded, military-political confrontation where dangers and risks are chillingly real — but where tourists may go nonetheless — is called Panmunjom. It is located in a no-man's land called the Demilitarized Zone (DMZ) between North and South Korea. Not long ago, I joined a group of travelers for a six-hour excursions from Seoul to the DMZ. I half expected that the experience would be more theatre than threat. I was mistaken. This is what happened.

To obtain a necessary security clearance, reservations for the trip must be made 48 hours in advance; name, nationality and passport number are submitted to the Korea Tourist Bureau (offices in major hotel lobbies). This is the only travel agency authorized by the United Nations Command to conduct tours to Panmunjom.

The day before departure I was told that I must carry my passport and could bring a camera, but that the dress code for the trip would be strict: no bluejeans, no "sports shoes," no long, unkempt or hippie-style hair. One member of the group asked if Adidas sneakers would be considered sport shoes. Answer: don't take a chance, wear something conservative.

On DMZ-Day, the bus picked up passengers at two hotels and was underway through the dreary, rain-drenched sprawl of downtown Seoul by 9:40 a.m. Our group was about equally divided between Japanese and Americans. There were two guides, a man and a woman, both Korean. "My name is S.J. Kim," the man introduced himself, "please just call me Kim." He was short and wore a dark business suit. "We are going to be speaking poor English today. We will ride bus for three hours and take tour of DMZ for three hours. You will be back at your hotel by four pee-em. Please — sometimes I will tell you that there is to be no smoking and sometimes I will say no pictures. Kindly obey. It is very important . . . ."

This was then translated into Japanese, which took longer than in English. An American muttered, "What's he telling them that he didn't tell us, you suppose?"

Panmunjom, a one-time farm village of 700 population, is 27 miles north of Seoul on Highway 1. This road is the sole remaining link between South and North Korea. Every other means of communication has been cut off and sealed for nearly 50 years. "If we just want to send a letter to the North, we must send it to China first," Mr. Kim explained with a laugh.

Highway 1 winds through Seoul's endless suburbs before reaching farm country. Along the way, Mr. Kim provided a history refresher: North Korea attacked South Korea across the 38th Parallel on the morning of June 25, 1950. The war between the communist regime to the north and United Nations forces supporting the republic in the south lasted three years, seesawing back and forth. After more than two million Koreans had been killed, an armistice was signed on July 27, 1953. "Korea was 90 percent destroyed," Mr. Kim said with an inappropriate smile. "It was a big loss."

While Kim's partner switched to the Japanese translation, an American woman whispered to her companion. "I didn't wear a bra. Do you think they'll call that hippie?" Her friend answered quietly. "I didn't wear one either. Who can tell?"

No peace treaty has ever been signed between the two Koreas. Only the longest truce in modern history stands between these fraternal but mortal enemies and the resumption of open war. The line of that truce is the DMZ, 2-1/2 miles wide and stretching 151 miles from one side of the Korean peninsula to the other.

Panmunjom, the village where the armistice was signed, lies within the zone, near its western end.

Kim previewed the day. "The place we are going at Panmunjom is called Joint Security Area. You will have to sign a waiver of responsibility form in case something happen. You scare?" Kim laughed. "No need. Forty-eight thousand people visit DMZ last year. Nothing happen."

At 10:45 a.m., the bus pulled off the highway and into a parking area in front of a group of monuments. Kim explained that one was a Philippine War Memorial, one a monument honoring war correspondents and one, called the Human Bomb Monument, marked a heroic deed by ten South Korean soldiers. The rain was now coming down in a steady, gray curtain. Ten minutes were provided for those who wanted to get out and see the monuments. At first, no one moved. "You may take pictures," Mr. Kim encouraged cheerfully. A few hardy travelers huddled out under umbrellas. The Japanese tourists took pictures.

Returning to the bus, one man complained that his "office shoes" were getting wet. "I had some rubber-sole jobs, but I was afraid they'd call 'em sport shoes!"

We rolled north on a four-lane highway through a flat valley. There were rice fields on both sides and many plastic-covered greenhouses shaped like Quonset huts.

Mr. Kim now had more instructions. "By the way, when you are in truce building, it is very important not to touch anything. Also, North Korean soldiers may wave at you. Don't wave back. Most of all, do not point at them. This makes them very angry."

About 11 a.m., we reached Munsan City, population 30,000. Passengers wiped steam from the inside of the bus windows to see out. "This is the end of the rail line now," Mr. Kim said. "We used to be able to take the train all the way from Pusan in the south to China, but no more." Munsan was a distant blur. There was little traffic on the road here. Small ginseng plants grew under thatched straw shelters in the fields.

At Imjingak, Mr. Kim announced, "Military area, please now, no more pictures." The bus slowed, but did not stop; Kim explained that this crossing point over the Imjin River is the northernmost place on Highway 1 which may be visited by South Koreans. "So, because our citizens can not go on to Panmunjom, we have built a mini-Panmunjom for them here."

An exact replica of the Panmunjom truce negotiation building has been reconstructed for the benefit of South Korean tourists. There is also said to be a statue of Harry Truman, a "house of nostalgia" and a rusted-out locomotive headed north, symbolic of "every Korean's" deep desire for the reunification of his country.

"Thousands of our people rush here during Moon Festival to pray for reunion with the North," Mr. Kim said. Inexplicably, a long line of yellow and green taxi cabs waited in the rain at Imjingak, their headlights gleaming, their engines running. They were headed in the only possible direction, south.

We stopped at Freedom Bridge on the Imjin River. "Check passports here," Mr. Kim said as the door of the bus folded open. American soldiers were in the guard house at the end of the bridge. It was surrounded by coils of concertina wire. The bus waited for the formalities. A sign read, "All personnel are subject to search upon crossing Freedom Bridge. AR 190-22. By Order of Commanding General."

There was no passport check after all. "They trust that Korea Tourist Bureau do its job very well," Kim said with a self-serving laugh. We all put our passports away again. A man's voice grumbled. "What a lot of nonsense . . .passport, no passport. Probably could have worn bluejeans, too."

The steel bridge is dead straight and narrow. Its wooden deck planks rumbled under the bus. Helmeted American sentries, draped in wet ponchos and holding rifles, saluted and grinned faintly as we passed. They looked like Mauldin's GIs from the World War II cartoons. Willie and Joe. Below, the silt-gray Imjin mudflats were etched with vein-like greens.

"Thirteen thousand of our prisoners came home over this bridge after the war," Mr. Kim said. The last sentry saluted; the road became narrower as we left the bridge.

"We find big tunnel around here." Mr. Kim described a 500-meter tunnel that had been bored through by North Koreans "to infiltrate spies." It was 3-by-3 meters in cross section and 57 meters deep, built like a mine shaft. "We drilled 125 holes down from the surface before we found it."

Army trucks were parked in concrete revetments near the road. Two tanks crouched near some rice fields. Ordinary things began to acquire a look of menace. Kim explained about Unification Village which was nearby. It is a settlement of 550 farmers who continue to make their homes and their living in this dangerous area. In return for the hazards of this life, they pay no taxes and are not subject to military service. But they must be locked up in their houses each night by 10:30.

"We come soon to Camp Kittyhawk," Kim announced. "It is the advanced camp. We will have lunch. Western food and beef. Anyone who must have pork-meat, please tell me. You can buy souvenir here."

Kittyhawk, a half-mile south of the DMZ, looked like many other small military camps. It had paved streets and permanent buildings: a headquarters, a post office and what the army once used to call a mess hall Now it is a "dining facility." A recreation building, mischievously named The Monastery ("Home of the Merry Mad Monks of the DMZ") is where souvenirs are sold: key rings, T-shirts, belt buckles, plates to hang on the wall, postcards. There is also a small movie theatre, a pool table, a TV set, a bar. On the wall, a photo of General Mark Clark signing the armistice.

At 12:10 p.m., the group seated itself in the dining facility. Kim circulated among the tables, cheerfully repeating, "Military food but very tasty." A waitress put four glasses of undefined yellow juice on each table. A couple of Americans bought 90-cent highballs at the PX bar. The bra-less girl smoked nervously; she had pulled on a sweatshirt. The man with the wet shoes flexed his feet and assessed the damage. The Japanese tourists sat in a silent grouping. The electronic chirping of space invaders being shot down came from a video game in the bar.

Lunch, when it arrived, was two slices of lukewarm gray meat under thick gravy with mashed potatoes and carrots. The food does not qualify as "tasty." There is no coffee or dessert. The meal is consumed in about 20 minutes. We are told to assemble for a briefing in an adjacent building. The rain has stopped, but the skies remain gray, sodden and low.

We enter a small auditorium. A sergeant is on the stage, holding a pointer. He is brisk, businesslike and slightly intimidating. Photographs and a map are projected on a screen for orientation, then the sergeant sums up.

"The Joint Security Area is a hostile zone. The form we are giving you to fill out releases the United Nations Security Forces from all responsibility. At all times during the one-hour tour you are about to take, there will be over 150 armed men who are well trained to look after your security. I must remind you, however, not to make any arm or hand gestures while in the presence of the North Koreans. They consider almost anything an obscene gesture. Now please read and sign your visitors declaration."

The official document told a story which brought a collective silence to the room. We read: "During the period from October, 1966 to August, 1967, 160 hostile acts were committed south of the Military Demarcation Line by the North Koreans. In addition to direct attacks against United Nations military positions, these acts of violence included mining of roads, destruction of sleeping quarters and blowing up of civilian passenger trains. One of the most vicious attacks was the machine gunning of the advance camp on 28 August, 1967. During this attack, three were killed and 26 were wounded. Your requested visit to the conference site at Panmunjom entails travel over the same routes where this attack occurred. As recently as 18 August, 1976, an overwhelming force of club- and ax-wielding North Korean guards assaulted UN Security Personnel while they monitored a civilian tree-trimming work party. In this attack, two UNC officers were beaten to death.

"With this in mind, the following certificate must be read and signed: I recognize that my impending visit to the Joint Security Area at Panmunjom entails entry into a hostile area and that I am subjecting myself to the possibility of injury or death as a direct result of enemy action . . . ."

The mood of the day had suddenly changed.

We all signed and received a guest badge to wear. We left the building and boarded our bus at 1:30 p.m. Mr. Kim was gone now, his place taken by the sergeant. He checked each of us: no bluejeans, no Adidas. The interior of the bus was quiet as we pulled out for the DMZ. No one complained about the smoke from many cigarettes which were lighted. Seoul and our luxury hotels seemed very far away indeed.

In about five minutes we came to a tank wall, a giant fortification with barbed wire, searchlights, guard towers. "Eleven men were killed here in '67," Sergeant says, matter of factly. Inside this barrier, soldiers in full battle gear, their faces smeared with camouflage make-up, were manning gun emplacements. Ammunition was visible, the real stuff. "No photographs here," Sergeant announced. "This is US Second Infantry. They don't allow pictures."

We come to a place which Sergeant says is Checkpoint One. "I will be surrendering your visitors declarations now," he says, as if giving each of us a last chance to change our mind. He passes the handful of papers to an MP who salutes the bus. We move slowly along a two-lane road. There is no other traffic. We approach a hill which bristles with defenses. "Guardpost Collier," Sergeant says. "From the top, we can see 14 to 17 kilometers into North Korea."

We pass an intersection. "That dirt road leads to Kaesong Dong," Sergeant points out. This town is otherwise known as Propaganda Village. Six to 12 hours of Communist propaganda is broadcast from its tall radio tower every day. Otherwise, the village is empty, a piece of clever stagecraft. "They bus in a 'population' every morning," Sergeant explains, "school kids and all. Then they take 'em away at night. Nobody lives there."

Some barracks-like buildings come up on the side of the road. "The men who live here can arm themselves and board their trucks in 60 seconds," Sergeant says, "and be in the Joint Security Area in two minutes." There seemed some comfort in that fact.

"From this point on," Sergeant says, "I must warn you that you are under constant observation by North Korean soldiers with high-powered scopes and cameras. You are surrounded on three sides by North Korean territory. This is designated an invasion route and a free-fire zone. Every soldier here is entitled to use his weapon in his own defense and in the defense of others without specific orders."

We enter the Joint Security Area at 1:45 p.m. The bus stops in front of a row of low buildings, painted in the sky-blue color of the United Nations flag. Sergeant leads the group into one of the buildings. At the center is a long table covered with a green cloth. Microphone cables bisect its long axis. The wires are the border between North and South Korea. At this table, representatives of two nations still technically at war have met hundreds of times in the last five decades, always in hostility.

Our group surrounds the table, listening to Sergeant warn against touching anything in the room, particularly the small North Korean flag standing at the end of the table, side by side with a UN flag of approximately the same size.

By walking around to the north side of the table, it is possible to say that one has been in North Korea. Several of the tourists do this, feigning fear and laughing nervously.

North Korean soldiers watch our group through windows on both sides of the building. They seem amused, but not particularly threatening. One wonders, almost suicidally, what the effect would be on world peace if one of these Americans were to make a genuinely obscene gesture at this moment. Just as the thought ignites, Sergeant says it is time to leave. World peace is saved. We troop out. Some in the group hang back long enough to take a last photo of the North Koreans.

We cross the street and mount a pagoda-like observation tower. From this point it is possible to see "enemy" soldiers in several directions, all of them equipped with binoculars, cameras and guns. The atmosphere is palpably tense. One wonders how it is possible to maintain such a degree of animosity for so many years.

On the way out of the Joint Security Area, the bus circles near a small concrete span over a river. It is the Bridge of No Return; it leads to North Korea. Nearby is the ugly, decaying stump of a poplar tree which was being pruned for better visibility in the summer of '76 when two American officers were attacked and killed with axes. The bus does not stop, but cameras click like a swarm of beetles as we pass the tree.

Back at Kittyhawk, we surrender the visitors badges, say good-bye to Sergeant and pick up Mr. Kim for the ride back to Seoul.