Wired Science

A Guide to Some of the World's Most Endangered Archaeological Sites

The preservationists at CyArk, a non-profit organization that uses laser scanners to record three dimensional digital images of endangered historic structures,  have their work cut out for them. (You can join Ziya Tong on a trip with them to Colorado's Mesa Verde National Park here.)

All over the world, hundreds of the most important man-made historical sites   are being worn away by weather, insects, animals - and most especially, the impact of people in the present. According to the World Monuments Fund, the impact of human activity - including pollution, tourism, urbanization, armed conflict and climate change - are now the greatest threat   to the world's cultural heritage sites.

There's no question that many, if not most, of these sites will continue to deteriorate. Some will be destroyed completely, the way the Taliban destroyed the Bamiyan Buddhas in Afghanistan.  They can't all be  saved, but by using fast and relatively cheap digital imaging technology, CyArk aims to create detailed records of many of these sites while they're still intact.  3-D models are archived on  CyArk’s website, where they can be explored by archeologists, academics and anyone else who's interested. They can even be used as blueprints from which parts of the buildings can one day be re-created. CyArk's archive currently contains records of sites from Cambodia to Peru. Coming soon: the ruins of Nineveh, in Iraq. 

Here's a sampling of some of the most seriously threatened sites - some of which CyArk has already documented:

Tikal, Guatemala: Deep in the jungle, a collection of massive stone temples and palaces mark the spot where one of the foremost cities of the Mayan Empire stood from the 6th century BC to the 10th century AD. Though the area was declared a protected national park in 1955, Guatemalans fleeing the poverty and wartime violence of the country's highlands have flocked there and established illegal settlements around and within the park's boundaries. Add to that ever-growing hordes of poorly-regulated tourists, who in turn generate mountains of garbage and waste, and you've got a recipe for damaged buildings and monuments. The United Nations recently began working with Guatemalan authorities to better manage the tourist traffic.

Abu Mena, Egypt: This early Christian holy city was built near modern Alexandria beginning in the 4th century AD. But its church, basilicas, monasteries and other buildings are now literally collapsing thanks to a World Bank-funded land reclamation program which has led to a rise in the local water table. Encroaching groundwater has liquefied much of the clay soil under the city, opening huge underground cavities and causing several structures to cave in. Egyptian authorities have closed many of the remaining buildings to the public and filled their bases with sand, and are digging trenches to control the groundwater.

Angkor, Cambodia: Once the largest pre-industrial city in the world, Angkor was the site of several capitals of the Khmer dynasty, and its temples constitute the finest collection of Khmer art and architecture. The site was badly neglected during the political violence that engulfed Cambodia from 1972 to 1989, and was damaged by encroaching vegetation and soldiers shooting up its monuments. The first round of conservation efforts, led by India, only added to Angkor's troubles. The conservators cleared vegetation with fire and used harsh abrasives to clean buildings, damaging the stone. In 1992, UNESCO added Angkor to its list of endangered world heritage sites, and Cambodian authorities took control of the area. Since then, preservation efforts have made substantial progress. 

Church of the Nativity, West Bank: Set on what is reputed to be the birthplace of Jesus Christ, this church, founded in 330 AD by Emperor Constantine, is one of Christianity's holiest sites. But its rotting roof timbers haven't been replaced since the 19th century, and rainwater is seeping into the building, damaging walls and mosaics. The exterior walls have also been damaged by bullets in fighting between Israelis and Palestinians. As the World Monuments Fund dryly notes, "For the sit to be preserved, its three custodians—the Greek Orthodox Church, the Armenian Orthodox Church, and the Franciscan order—would have to coordinate their efforts, but such a collaboration has not occurred in nearly a thousand years."

Machu Picchu, Peru: The remains of this ancient Incan mountaintop city were re-discovered  in 1911, and the site was added to UNESCO’s World Heritage List in 1983. Tourism has exploded in the years since: In all of 1992, a total of 9,000 tourists visited the site, but by 2006, over 4,000 were coming every day. Peruvian officials, however, have done little to protect the site, putting their energy instead into development projects like a proposed tram to make visitor access easier.

Kilwa, Tanzania: A collection of centuries-old stone and coral buildings, including a mosque and a fort, dot the southeast coast of Tanzania - but may soon disappear into the sea, thanks to coastal erosion and rising sea levels.

Ayaz Kala, Uzbekistan: In the 1940s, an archaeologist in this central Asian republic uncovered the towering mud-brick remains of three fortresses which had been abandoned 1,300 years earlier. Left exposed to the elements ever since, the structures have decayed badly - a process only made worse by the growing number of tourists who now visit them.