By Kate McGeown
BBC News Online
The ancient temple complex at Angkor is Cambodia's pride and joy, and is even depicted on the national flag.
Looters are usually locals hoping to earn a few dollars
But while the scale and intricacy of Angkor is simply breathtaking, it is almost impossible not to notice the scars wrought by decades of looting and destruction.
Hundreds of statues no longer have heads, some of the walls are etched with graffiti and large pieces are missing from columns and archways.
Since the late 1990s, guards have been brought in to patrol the vast temple network. According to the United Nations cultural organisation, Unesco, the scale of looting has dropped dramatically.
But the same cannot be said for Cambodia's other sites, of which Unesco has so far identified 3,500.
Many are in remote areas that are difficult to access and even more difficult to police.
"Hundreds and hundreds of sites are being dug up every day," said Dougald O'Reilly, the director of Heritage Watch, an independent group aiming to safeguard Cambodia's cultural heritage.
Mr O'Reilly said that too much of the world's attention had been focused on the World Heritage site of Angkor, to the detriment of other areas.
"Many of these other sites go back to the bronze and iron ages," Mr O'Reilly told BBC News Online.
"We've found burial sites such as Phum Snay, with evidence of warrior cultures, with swords, helmets and shields," he said. "Some of these have never been found before in South East Asia."
For Heritage Watch, the theft of these artefacts is just as damaging as the removal of sculptures from temples.
"In some parts of the country, you can buy 10 kilograms of ancient iron from these cemeteries for just 25 cents," said Mr O'Reilly. "It's very openly sold in local markets."
Of course, the destruction of Cambodia's heritage is nothing new.
Over the centuries, numerous different groups - including Thai and Vietnamese invaders, French colonisers and Khmer Rouge guerrillas - have trampled over Cambodia's ancient sites, each contributing to the damage.
But it was not until the colonial period that the Western world became aware of the treasures hidden in Cambodia's forests, and a potential market was created.
Both local people and professional looters realised the profits to be made and began to strip these monuments of all they could get their hands on.
Since then, the rules governing the worldwide trade in antiquities have become much tighter, according to Robert Knox of the British Museum's Department of Asia.
"If you can't prove it has been obtained legally, we can't buy it," said Mr Knox.
But he admitted that as long as there were unscrupulous private collectors - in Europe and the US, as well as other Asian countries such as Thailand and Japan - it was very difficult to prevent objects being smuggled abroad.
"It's like cocaine. As long as there are end-users, looting will continue," Mr Knox said.
According to Etienne Clement, the director of Unesco in Cambodia, the relatively new trade in pre-Angkorian antiquities is presenting even greater challenges to international trafficking police.
"These pieces are small, and some of them have never been photographed before so they are very difficult to spot," he said.
"They can even be sold on the internet."
He said that a piece of exceptional value could raise up to $50,000.
While international criminal networks are often behind the illegal sale of Cambodian antiquities, the people who physically remove the objects are usually local people.
Heritage Watch hopes a new education campaign will persuade Cambodians not to participate in the "cannibalisation of their own culture and identity".
"The only feasible method to fight the destruction is through education," said Mr O'Reilly.
Time also alters the appearance of Cambodia's temples
Heritage Watch aims to show people they can benefit from a long-term approach to making money from their past.
It hopes to build museums next to excavation sites, to display the artefacts exhumed.
"This initiative will demonstrate the possibility of long-term sustainability," said Mr O'Reilly, adding that local people could then sell T-shirts and postcards to tourists visiting the museums.
Hope for the future
The ancient city of Angkor - which contains the world famous Angkor Wat as well as hundreds of other temples - is now guarded by special heritage police.
The guards are provided by a government-run organisation called Aspara, named after the heavenly dancers featured in many of Angkor's famous carvings.
"In the main tourist areas of Angkor, I can say confidently that hardly any looting goes on any more," said Ang Choulien, the head of Apsara's department of culture and research.
If it is possible to stamp out looting in Angkor - which covers an area of over 150 square kilometres - then maybe there is a chance for other areas of Cambodia too.
But there is still a long way to go.
"Cambodia's culture is very rich, but the country itself is very poor and weak," said Etienne Clement. "It's an ideal situation for illegal trafficking."