The sight of 8,000 human skulls in a glass shrine stuns visitors into silence.
Outside, where cattle usually graze, human bones sometimes come unearthed after heavy rains.
In Cambodia, nine miles (14.5 kilometers) from Phnom Penh, the "killing fields" of Choeung Ek have become a tourist attraction, horrifying and fascinating. Choeung Ek is one of thousands of other such sites around the country where the Khmer Rouge practiced genocide during the late 1970s.
"There are two things you must see in Cambodia," says Scott Harrison, a traveler from Australia. "Obviously one is Angkor Wat. But the other is the killing fields outside Phnom Penh."
In the chronicle of 20th century horrors, Cambodia ranks high. For much of the last three decades, Cambodia has suffered through war, political upheaval and massive genocide.
Recently Cambodia has begun to revive. Its dark past is part of the reason: Tourist curiosity about Cambodia's genocide has become big business.
"Tourism has increased by 40 percent every year since 1998," says Chhieng Pich, economic counselor at the Cambodian embassy in Washington, D.C. "Nearly all tourists that visit Cambodia will go see Angkor Wat. Over 30 percent will visit the killing fields, too."
Few sights in one country can differ more markedly. Angkor Wat, the early 12th-century temple rediscovered in the 19th century (and designated a World Heritage Site in 1992 by UNESCO), reflects a profound spirituality.
1.7 Million Cambodians Dead
The killing fields document death. From 1975 to 1979, Pol Pot and his Khmer Rouge soldiers killed 1.7 million Cambodians, or 21 percent of the population, according to Yale University's Cambodia Genocide Program.
A soccer-field-sized area surrounded by farmland, the killing fields contain mass graves, slightly sunken, for perhaps 20,000 Cambodians, many of whom were tortured before being killed. The bordering trees held nooses for hangings.
A memorial building stands in the center of the killing fields. Many of the skulls inside were pulled from the mass graves.
Hundreds of Cambodians now make a living by guiding visitors through the killing fields and other genocide-related sites. Many guides tell harrowing personal stories of how they survived the Khmer Rouge, often by becoming refugees in Thailand.
Guides explain that bullets were too precious to use for executions. Axes, knives and bamboo sticks were far more common. As for children, their murderers simply battered them against trees.
The grisly memories translate into income. "Tourist dollars and capitalism are helping me come to terms with my country's history—and my own," says a Cambodian guide at the killing fields who didn't want to give his name. He lost his grandfather and uncle to the Khmer Rouge.
Tuol Sleng Museum of Genocide
"It's good tourists are coming here interested in Cambodia's past," says Stephen Bognar, a liaison officer for WildAid Cambodia, a nonprofit conservation organization. "They're boosting the country's economy and helping out the people."
Another notorious site is the Tuol Sleng Museum of Genocide in Phnom Penh. Once a high school, Tuol Sleng became a torture camp, prison and execution center.
Today the place looks benign, with palm trees and grass lawns in a suburban setting. From the outside, Tuol Sleng could be a school anywhere in the world. But inside are weapons of torture, skulls, blood stains and photographs of thousands of people who were murdered.
The scene just outside is also heartrending. Amputees of all ages beg near refreshment and souvenir stands where tourists congregate. The Khmer Rouge may be long gone, but many of the land mines they laid are still killing and maiming.
In a country where the annual per capita income is U.S. $260, begging can pay off.
"Beggars can easily make [U.S.] $3 to $4 dollars a day," says Lim Sehyo, a Phnom Penh taxi driver and guide. "If you work it out, that's over [U.S.] $1,000 a year."
As taxis full of tourists arrive at the killing fields, guides and beggars approach. Horror, memory, education and livelihood commingle at the site.