Spectacular Sunset Rush Hour

July 4, 2007 — -- After years of neglect threatened to destroy the temples of Angkor during the brutal regime of the Khmer Rouge, this wonder of the world is now at threat for a different reason — too much interest.

The temples were built between the ninth and 15th centuries and now face the modern threat of tourism, as millions of visitors arrive to see the more than 100 Hindu and Buddhist monuments spread across 50 square miles in Cambodia.

"The ruins of Angkor are one of the marvels of the world," John Stubbs of the World Monument Fund told ABC's Mark Litke. "There's no doubt about that."

Stubbs is at the forefront of a global effort to preserve and restore Angkor, and has spent 15 years in Cambodia to help piece together a vast archaeological jigsaw puzzle.

While Stubbs' work has helped to save Angkor and turn it into one of the world's premiere destinations for cultural tourism, the location's salvation may ultimately turn out to be its curse.

There's literally been a tourist invasion. In the 1990s, Angkor attracted just a few thousand visitors a year; by the end of 2007, a total of 2 million are expected to climb up, down and through the ancient ruins.

They arrive by planeload, busload, on motorbikes and even on elephants.

Visitors once had to hack through jungles to reach Angkor. Now, the route to the temples is packed with traffic jams, especially by the end of the day when more than 3,000 people assault the highest temple in the complex to watch the sunset.

In the adjacent town of Siem Reap, there were just two hotels a decade ago — now, there are more than 102, along with shopping malls, pizza joints and massage parlors.

It's hardly the serene Angkor experience some tourists might expect, as one woman told ABC News, "I think it takes away from it, I do."

But, another visitor said, "I don't. I feel that the importance of this place deserves people to watch it, see it, witness it."