PHONSAVAN, Laos — It should be hard to go missing on the Plain of Jars. But hundreds have.

Flying into this rural region in northern Laos, one sees lushly blanketed mountains and valleys give way abruptly to an arid expanse of pockmarked browns and yellows. It looks a bit like an oversize golf course in the Australian Outback. This is Xieng Khuang Province, which is known outside Laos mainly to archaeologists fascinated by the great Asian mystery to be found there: Thong Hai Hin, or the Plain of Jars, a plain strewn with hundreds of giant stone jars of uncertain origin.

A lesser-known fact is the province’s status as the most heavily bombed place on Earth.

The rice paddies of Cambodia and Vietnam were not the only killing fields of the Indochina wars. Xieng Khuang was a strategic link between Northern Laos and the western highlands of Vietnam. When the Pathet Lao communist forces and North Vietnam troops took the plain in 1964, U.S. pilots began a decade-long bombing campaign.

Both sides contravened the 1962 Geneva Accord, which recognized Laos’ neutrality during the Vietnam War era and forbade any foreign military presence there. The ensuing nine-year battle was kept under tight wraps and became known as “the secret war.”

Keeping news of this war from an increasingly critical outside world must have been difficult: Between 1964 and 1973, some 2 million tons of bombs were dropped on Laos, averaging one plane-load every 10 minutes, 24 hours a day, for nine years. Some 300,000 tons were dropped on Xieng Khuang alone — two tons per civilian. The sparse vegetation is a reminder of the thousands of liters of defoliants and herbicides that were also unloaded there. Residents fled, taking refuge in nearby caves; some 10,000 more were slaughtered. It’s ironic that the most commonly accepted theory for the jars — which are said to date back to the time of Christ’s birth — is that they were once used as sarcophagi.

Since the old capital, Xieng Khuang, was flattened during the war, the region’s hub today is Phonsavan, a dry, dusty two-street town. Even the local school, a wooden building surrounded by rusted barbed wire, somewhat resembles a stable.

Yet Phonsavan has idiosyncratic charms: The Volga sedans bounce along dirt tracks with pot holes the size of bomb craters (some doubtless are); a woman dressed in elaborate hill-tribe garb alights from a “tuk-tuk,” or three-wheeled taxi, sporting Nike sneakers; grubby dogs, braving the midday heat, scamper past a guitar-strumming youth perched atop a huge bomb casing.

The Volgas, which are almost as plentiful as the ubiquitous tuk-tuk, belong mostly to young, cocky entrepreneur wannabes, who crowded inside the town’s shed-in-a-field airport and pleaded with arriving visitors to utilize their “authorized” guidance services. Authenticating the claims of the more ambitious were business cards, scraps of paper on which name and phone number were scribbled.

Tuk-tuk drivers hanging back in the shade outside offered a more economical alternative.

There’s really only one place to visit here, so Mr. Lae didn’t bother with questions — other than “How much?” — as he steered his tuk-tuk along a track heading out toward the jars.

It was a bone-rattling trip, and a suffocating one: dust billowed up from the road, enveloping the open-back vehicle. Crawling past a herd of cattle lazily making their way across the track, Mr. Lae glanced over his shoulder with a sympathetic smile: “Those Volga boys,” he seemed to say — “they ain’t so stupid.”

Most of the jars are clustered at three sites, each located on a hilly meadow commanding an uninterrupted view of the flat plains and the low hills bordering them in the distance. The peacefulness seemed to confirm the theory that this place had been a kind of cemetery.

However, much of the evidence concerning the jars’ former use vanished decades ago with looters, and research to verify a theory that there may be other buried urns linking the three sites is stymied by the presence of unexploded ordinance.

At Ban Ang (Site 1), jars are scattered in a line stretching from one hillock to another about 500 meters away. Linking them is a narrow, well-worn path — from which you’d be ill-advised to stray.

Yet many local villagers, especially young children, have done just that.

For the people of Xieng Khuang, the secret war did not end in 1975. Unexploded ordinance has cost them dearly ever since, in terms of both casualties and loss of land. Although projects to clear the area continue, even today 30 or 40 children are reportedly killed every year by UXO such as those left behind by cluster bombs, or “bombis” as the locals call them. One Phonsavan resident estimated that the figure could be as much as three times higher.

The remains of detonated ordinance is also much in evidence, and some villages in Xieng Khuang look like military scrap yards. At one hamlet near the picturesque Site 3, bomb casings had been utilized as fences and house stilts, while aircraft fuselage was used as roofing. This debris, like the unexploded ordinance, is also a legacy of the secret war, belonging to some of the dozens of U.S. planes that were quietly put into action during the nine-year conflict.

In the early 1960s, the United States, in conjunction with noncommunist forces in Laos, devised a system whereby U.S. military personnel could serve as “in the black,” or clandestine, pilots. Top air force officers were mustered out of the military to perform military duties as civilians. The war was so secret that the country’s name was never mentioned; Laos simply became known as “the other theater.”

The Ravens, the code name for U.S. pilots operating in Laos, were officially on loan to the U.S. Air Attache in Vientiane. Unofficially, they were sent to outposts like Long Tieng, located between Vientiane and Xieng Khuang and the clandestine HQ for the 9,000 troops reportedly stationed in “the other theater.” Their field commanders were the CIA and the U.S. ambassador.

The necessity of keeping their numbers small meant that some pilots worked up to 12 hours a day.

The casualty rate among the Ravens was extremely high — about 50 percent, according to Christopher Robbins in his book “The Ravens.” Reportedly, 400 died in combat and a further 600 went missing in action.

The search for many of them continued long after the war ended. Sousath Phetrasy, a Phonsavan hotelier and bounty hunter, had evidence that some were still living in Xieng Khuang as late as 1990.

In the early 1990s, Phetrasy was engaged by relatives of three U.S. pilots believed to have bailed out on a bombing expedition over the Plain of Jars. His search, he said, was going smoothly until the U.S. government intervened and banned him from searching further.

“When the Pathet Lao took over Laos in 1975, the U.S. government tried to change the MIA lists to KIA (killed in action),” Phetrasy explained. “Many American families disagreed with that change and established a POW organization, and hired me to do the job.”

When Phetrasy was 10, the secret war had reached its peak and he was sent to China by his parents, who, he says were well-known Pathet Lao “revolutionists.”

Not adapting well to his new home, he “escaped” back to Laos “by myself, with no map,” ending up in Sam Neua Province, which borders Vietnam on Laos’ northeast border and served as the Pathet Lao’s wartime headquarters.

It was there, Phetrasy said, that he came across several U.S. POWs, who taught him English in the caves where they were being held.

Some 15 years later, Phetrasy became involved in the search for three such soldiers almost by accident. His father, who had been the leader of a Pathet Lao camp in Vientiane during the war, was believed to hold information on U.S. POWs in Laos. “His name was well-known, especially among Americans who believed he held secret information about U.S. soldiers,” he said. “So some families contacted him for information, but he refused. That’s where I came in.”

Since 1990, Phetrasy has undertaken searches for three U.S. MIAs: Albro Lynn Lundy Jr., Peter Dean Hesford and Morgan Jefferson Donahue.

Phetrasy admitted that the $2 million bounty he had been offered to find out what had happened to the soldiers “made me crazy to accept the adventure.”

He had already gathered substantial information when the U.S. and Laos governments ordered him to stop, saying his activities interfered with their own searches. “They said this was their duty, not mine,” he said.

“They asked me to work for them and forced me to reveal my contacts. I found out later that those contacts had been arrested and thrown in jail. Later, they came and tried to hurt me. They thought I had betrayed them. . . . It was the biggest trouble of my life,” he added.

By that time, Phetrasy had obtained “70 percent verification” that a U.S. pilot was located “somewhere in a remote area between the Laos-Vietnamese borders,” he said. He would not reveal the soldier’s name, but said he believed the man had been returned to the U.S. a few years ago.

The search for other MIAs and KIAs continues, Phetrasy added. “Right now the U.S. and Laos governments are still looking for MIAs in Laos, but it’s got nothing to do with me,” he said, adjusting his Ray Bans.

Of the $2 million bounty, Phetrasy says he never received a cent. Today he makes his living running a hotel and guide service in Phonsavan.

But remnants of his search for U.S. soldiers and his obsession with a war that separated him from his parents are in evidence. In the courtyard of his hotel, Phetrasy boasts a collection of about a dozen machine guns, all collected from around the Plain of Jars. They may have belonged to MIAs he believes are still alive in the region — men still unsure of the reception they would get if they returned or those who have settled and made families there.

“You’d think it would be difficult to go missing on the Plain of Jars,” he said. “But there are many who never found their way back home.”

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