The Global Heritage Fund named 10 sites facing "irreparable loss and destruction."
"These 10 sites represent merely a fragment of the endangered treasures across Asia and the rest of the developing world," Jeff Morgan, executive director of the fund, said, presenting the report, "Asia's Heritage in Peril: Saving Our Vanishing Heritage."
The architectural gems from Asia's ancient and sophisticated cultures are struggling in the face of economic expansion, sudden floods of tourists, poor technical resources, and areas blighted by looting and conflict -- in other words, the pressures of rapidly modernizing Asia.
"We're looking at these millennial civilizations leapfrogging into the 21st century at a kind of pace that is unheard of, unprecedented," said Vishakha N. Desai, president of the Asia Society, which hosted a conference based on the report.
Kuanghan Li, head of Global Heritage Fund's China program, underlined the urgency in a presentation on work to preserve Pingyao, one of China's last surviving walled cities. The stunning fortifications are impressively maintained and floodlit.
But "up to 20 years ago, there were hundreds of similar walled cities left in China," she said. "They have been demolished."
Experts said that global architectural preservation efforts are poorly coordinated and targeted, with the UN cultural body UNESCO focusing almost entirely on sites in already wealthy European countries, rather than in places like Latin America or Asia.
More than 80 percent of UNESCO World Heritage sites are located in the 10 richest states, the Global Heritage Fund said.
Elsewhere, "heritage is being dramatically undervalued," Morgan said, warning that the endangered sites were doomed without quick help. "We're going to lose them on our watch in the next 10 years."
Shirley Young, head of the US-China Cultural Institute, said the importance of such work goes beyond being "just about beautiful buildings, beautiful sites."
"I think we'd agree," she said, "that a world without history is a world without soul."
Still, experts highlighted stories of inspiring success stories.
John Sanday, a specialist who has spent years trying to bring Angkor and other Cambodian sites back from the brink of collapse, showed dramatic before-and-after photographs of majestic temples that he first encountered two decades ago.
"The trees had literally just taken over and strangling the building, pulling it apart," he said, pointing to ruins that had been made structurally sound once again -- although now under threat from tourism.
"We really hope with a concerted effort we can save these places," Morgan said.
The top 10 endangered sites in Asia, according to the Global Heritage Fund, are:
1. Ayutthaya in Thailand, a former Siamese capital known as the "Venice of the East."
2. Fort Santiago in the Philippines.
3. Kashgar, one of the last preserved Silk Road cities in China.
4. Mahasthangarh, one of South Asia's earliest archeological sites in Bangladesh.
5. Mes Aynak, an Afghan Buddhist monastery complex on the Silk Road.
6. Myauk-U, capital of the first Arakenese kingdom in Myanmar.
7. Plain of Jars, a mysterious megalithic site in Laos.
8. Preah Vihear, a Khmer architectural masterpiece in Cambodia.
9. Rakhigari, one of the biggest, ancient Indus sites in India.
10. Taxila, an ancient economic crossroads in Pakistan.