The DMZ is one of the most popular tourist destinations in South Korea, attracting more than a million visitors a year. Shortly after starting out from Seoul toward the border, a mere forty-five miles away, the sprawl of the city gives way to farmland, and land-mine warning signs appear. The Technicolor-hued graphic of a farmer and soldier being exploded reminds travelers that the vast green expanse of the DMZ—155 miles long and two miles wide—is maintained in part by the millions of mines embedded in the soil. No peace treaty was ever signed when hostilities between the countries ceased in 1953, and mines are still being planted today. (South Korea, which is the size of Indiana, maintains a standing army of nearly a million.) My cousin was assigned to be a mine specialist while serving his mandatory two years, and he told me that DMZ duty was the most arduous of posts. Because it is an active war zone, daily routines are brutal and the level of alert is always high. Each day two million soldiers stare one another down from opposite sides of the barbed wire. But for some, service means acting as a tour guide.

Military zones are normally restricted, but South Korea offers carefully orchestrated tours that give visitors access to the DMZ at select viewing points. (North Korea offers a limited number of tours, too, along a route planted with signs denouncing America and championing reunification; nevertheless, a recent advertisement on the back cover of Time Out beckoned New Yorkers to “Asia’s Best Kept Secret: Vacation in North Korea.”) Having visited the southern border five times since 1996, I've seen the DMZ develop from an awkward spectacle of war-without-war into a professional, if still unnerving, enterprise, a scripted melodrama pitting national security against reunification.

A sign in the DMZ warning of land mines.

Tourists shop for the package that’s right for them, choosing among commercial tour companies or the United Service Organization. They are bused from hotels to the DMZ, where they pass Ferris wheels and karaoke halls on the way to glass-enclosed viewing areas, where soldiers narrate the history of the borderline. They proceed to a park built to console South Koreans with relatives in the North, where bronze statues of reunited brothers embrace, and on to the truncated Freedom Bridge, which spans a mosquito-ridden, peninsula-shaped pool. North Korea Hall offers dioramas depicting life in Pyongyang and duty-free souvenir shops selling purported links from the border fence and liquor from the North. Placards painted with uniformed chipmunks cheerily forbid photography. At Odu Mountain observatory, the northernmost point South Koreans may visit, tourists can don hard hats and enter the narrow infiltration tunnels—now sealed with concrete—that were drilled from north to south. Provincial authorities recently embarked on a campaign to “transform the DMZ from a place of political scars to a symbol of peace and ecology,” rebranding it as the Peace and Life Zone. A tour of the PLZ includes a trip to Hwacheon, along the Han River, where South Korea has built its colossal Peace Dam, which offers insurance against the release of water (whether by accident or intent) from North Korea’s own People’s Dam twenty miles upstream—a “water bomb” that would flood Seoul.

Panmunjom, the only piece of land in the DMZ where soldiers from the two countries come face to face on a daily basis, is the highlight of every tour. Soldiers are known to harass and taunt their adversaries on the other side and photograph their tourist charges. Panmunjom houses the Joint Security Area (aka Truce Village), a complex of buildings dedicated to diplomacy, where the actual Military Demarcation Line is accessible from either side. Sky-blue metal sheds straddle the borderline itself, and uniformed men—chosen for their height, fitness, and martial-arts abilities—march between the buildings and the concrete curbs that rise in between; they are separated by mere feet, their view of each other unobstructed.

On a recent trip, I stood before this scene with a group of tourists waiting to "cross" the border. In front of us was North Korea: a collection of guards in formation, looking at us impassively, a single Stalinist gothic office complex looming behind them. We entered the shed that spans the demarcation line, and an American soldier invited us to take turns stepping across it. When he signaled that it was my turn, I hesitated for a moment, then placed a foot into the North. I stood still for a moment, under the watchful eyes of the South Korean soldiers. Nothing happened. The other tourists kept snapping pictures of one another posed next to the guards—mementos from what one brochure boasts is “the most fortified border on Earth that only Korea can offer.” I stepped back into the South.

IN 2006, THE SOUTH KOREAN GOVERNMENT freed real estate developers and city governments to build on parcels of land that had until then been reserved for the military. As the real estate market surged, high-profile urban designers and planners were hired to build modern, ecologically sustainable megaprojects on open tracts of land. My grandmother’s hometown of Paju, a backwater military-base settlement located on the 38th parallel within a few miles of the North, has been turned into a massive construction site, awash in funds from the state and private developers. Most of the nine US bases that once dominated Paju have shut down, and in their places now rise immaculate emblems of cosmopolitan life. These include English Village, an English-only educational district modeled after a town in the United Kingdom; a publishing complex called Book City; and Heyri Art Valley, an expansive “arts incubator district.” But the work of progressive urban planning has its limits: When I visited my grandmother’s grave in 2008, my eardrums were still nearly punctured by the unmistakable reverberations of cannons being volleyed at a nearby firing range, tank treads were still carved into the roads ringing the city, and the streets were still crowded with open-air caravans of South Korean soldiers. As I returned to the DMZ over the years, I often wondered where the war was, exactly. Environmentalists and former political prisoners directed me beyond the border, toward the US military-camp towns, newly exhumed mass graves, and master-planned communities just south of the front line. Just as a tour of the DMZ is meant to convey the South’s freedom-and-democracy-enabled ascension, the economic development that has transformed the country in the past half century has suppressed evidence that might complicate that story: the crimes of the dictatorships that ruled from 1948 until the uprising of 1987, the purges that filled prisons with innocents and the countryside with corpses, and the complicity of the US military. The war had not begun in 1950 nor ended three years later; the battlefield had always been more diffuse, the enemies more various.

In recent years, seasonal typhoon rains and the earth-moving machines employed by developers have uncovered the evidence: mass graves containing victims of the purges carried out between 1945 and 1948, during the period of US military governance, and thereafter until 1960, during the reign of President Syngman Rhee. The purges were directed against South Koreans accused of being Communists, guerrilla fighters, or North Korean agents, and the truth about them was suppressed until the 1990s. Two hundred miles south of Seoul, in the county of Gurye, I met a farmer named Kim J. Y., whose father and uncle had been killed when he was six. Kim was working with the Truth and Reconciliation Commission, established to collect and verify the stories of survivors. He recalled how, as a child, he and other villagers had watched the military trucks creep up the mountainside packed full of people, then return empty. “Some of us heard the shooting,” he said, “but we didn’t recognize the sound.” This is how his father was killed.

Kim’s uncle was taken away because he was a member of the National Guidance League, a South Korean revival of the Japanese colonial organization used to register and keep tabs on members of the opposition after they were released from prison. Syngman Rhee not only continued this policy of registering dissidents but implemented quotas, which local officials filled by luring illiterate peasants with promises of farming benefits. By the start of the Korean War in 1950, the NGL claimed 350,000 members. They were systematically rounded up in the name of “preventative detention” and killed by state troops and police. Gurye’s mountainous station meant that villagers were also accused of aiding the guerrilla fighters who descended at night, in search of food. Eight hundred civilians were massacred in Gurye; the total number of bodies in the country’s mass graves could be as many as two hundred thousand.

Kim took me to the open excavation site where seventy people were killed on November 9, 1948. He had identified this grave in 2007 after noticing an indentation in the hill, which suggested that the decomposition of bodies had caused the topsoil to cave in. I crouched with him near the pit as he explained the pattern of the skeletal remains: The victims had knelt in a line at the edge of the pit, their hands tied behind their backs. They had been shot from behind, then were pushed or had fallen into the ditch. The next row of victims had followed close behind. Skulls rested on top of one another, ribs intertwined, kneecaps flush with other kneecaps. Kim told me that the soft skulls of children decompose more rapidly than the hard ones of adults, making them more difficult to find. The skeletons of women are often accompanied by the knots of ribbon that had tied their braids.

While at the DMZ the war has been collapsed into a jumble of symbol-laden buildings, vulgar keepsakes, and hollow rituals, in the countryside war is etched into the landscape with horrible clarity. When I provided a taxi driver with the location of the mass grave where I was meeting Kim, he casually told me, “The only reason my father was spared was because he signed away his land to the army commander.” As we drove to the exhumation site, he pointed out a yard where a large white building stood. “In that school, they gathered up people, locked the doors, and shot them all at once.”

FAMILY MEMBERS OF THE PURGE'S VICTIMS and the rare survivors began petitioning the government to investigate and apologize for the killings in 1960, after the fall of Syngman Rhee. For some, finding out the truth about their ancestors also meant freeing themselves from the stigma of having an alleged traitor in the family. For others, publicizing the massacres was an act of political resistance. All were silenced in short order: Park Chung Hee seized power the next year, declared martial law, established a military dictatorship, then commenced jailing and torturing the agitators, destroying the evidence. The civic groups reemerged after the 1987 democratic uprising, but the Truth and Reconciliation Commission wasn't formed until 2005. It took up a formidable task: “to foster national legitimacy and reconcile the past…by honoring those who participated in anti-Japanese movements and by exposing the truth through investigation of incidents of human rights abuses, violence and massacres that occurred throughout the course of Japanese rule until the present time.” Within a yearlong window for petitions, the commission received nearly eleven thousand; so far, it has investigated fewer than four thousand. When I asked a member of the commission how many mass graves exist, he answered, “Who knows how many? Think of the entire southern part of the peninsula as a giant civilian-massacre site.”

South Korea's conservative president, Lee Myung Bak, came to power in 2007 after a decade of progressive rule. He has embarked on a vigorous campaign to rout out dissenters in the government, schools, and media, going so far as to put bloggers on trial for criticizing his economic policies. True to his nickname, “Bulldozer,” he has pushed through massive public-works projects; the surge of government spending has kept the national economy afloat despite the global recession (and lined the pockets of the construction conglomerates, with which Lee has had close ties since his days as CEO of Hyundai Construction in the 1980s and 90s). His administration has done its utmost to block the Truth and Reconciliation Commission’s work. He replaced the commissioner with a crony who promptly withdrew its 2009 English-language progress report from circulation, claiming it was “biased” and translated incorrectly. His party tried to fold the commission into a subset of the human rights bureaucracy in order to stanch its funding. Following a public outcry, the commission was granted a two-year reprieve, but there is clearly a limit to the number of bones the country is willing to have unearthed.

South Koreans, young ones especially, are often said to have little interest in reunification, or in politics. They fear the potential costs of supporting North Korea if it transitions to free-market capitalism, but they are also wary of a reconciliation that threatens to unsettle the South’s image of itself. Much the same can be said for the reaction in both South Korea and the US to the exhumation of mass graves. (There is more at stake than national identity; the Bush administration referred to the American intervention in Korea as a template for democratizing Iraq and Afghanistan.) Even now, one rarely comes across evidence of the massacres. I remember how surprised I was when, in 2002, I found a 1950 article by the journalist James Cameron buried in a volume of censored news stories. The piece detailed the camps where Syngman Rhee kept political prisoners and was accompanied by the image of a spindly teenage detainee. After London’s Picture Post killed the story, Cameron wrote to the UN Commission on the Unification and Rehabilitation of Korea, describing “concentration camps” filled with civilians “convicted of nothing, un-tried…skeletal, puppets of string, faces translucent gray, manacled to each other with chains.” American soldiers stood by and photographed the scene with “casual industry.” The commission replied: “Most disturbing, yes; but remember, these are Asian people, with different standards of behavior.”

For all the talk of South Korea’s apathetic youth, it was tens of thousands of high school and college students who thronged the streets in the spring of 2008 to protest Lee’s agreement to reopen the country to US beef imports in the midst of a mad-cow-disease scare. That summer, Seoul was paralyzed by massive candlelight vigils organized on the Internet.

Protesters in downtown Seoul being sprayed with blue dye by riot police in 2008.

The government responded with violent crackdowns, drafting laws against nighttime assembly, using cell-phone or email records to track down protesters, and raiding the offices of left-leaning organizations in search of the “real” instigators. In time, the police turned to spraying tear-gas-infused jets of water and arcs of blue dye into the crowds gathered in downtown’s Gwanghwamun Plaza before advancing on them. Demonstrators and onlookers—myself among them—were branded; the police stalking the nearby cafés and restaurants where we fled could have no doubt of our guilt. Shortly thereafter, Hillary Clinton, who was at the time running for the Democratic presidential nomination, accused South Koreans of "historical amnesia."