GWEN IFILL: Thousands of Nepalese gathered today for prayer, ritual and ceremony, marking the end of a traditional Hindu mourning period held after the massive earthquake.

The death toll has grown to more than 7,800 people. Another 15,000 have been injured. Engineers are continuing to inspect thousands of damaged houses around Kathmandu. The earthquake also wrought considerable destruction and damage to religious, cultural and heritage sites throughout the region.

Jeffrey Brown reports on that, part of his ongoing work on Culture at Risk.

JEFFREY BROWN: The cremation of bodies continued this week in Kathmandu, as officials warned the death toll from the 7.8-magnitude earthquake could hit 10,000. Meanwhile, aid workers have struggled to reach remote areas, hampered by customs delays, closed roads and difficult terrain.

And villagers have grown frustrated by the pace and amount of relief getting to them.

MAN (through interpreter): It is so little. What can one do with this? Some have 15 to 20 people in their families. How long will it last? It won't last.

JEFFREY BROWN: The humanitarian crisis, the loss of lives, the need for food, shelter, and medicine, has been devastating in this mountainous country that is one of the world's poorest. At the same time, another kind of crisis has also unfolded.

This region once stood at the intersection of trade routes connecting India and China, and became home to a rich heritage of art and architecture dating back many centuries. Today, many of those sites, such as Bhaktapur Square and Patan Durbar Square, both in the Kathmandu Valley, are badly damaged.

CHRISTIAN MANHART, UNESCO Representative to Nepal: There are many of the temples which collapsed, and also many of the historical houses in which the families were living fell down. And in Bhaktapur, there are streets where we even cannot go at the moment, or this is very difficult to assess there.

Christian Manhart is the director of the United Nations Office of Cultural Heritage in Kathmandu.

CHRISTIAN MANHART: And then Patan Durbar Square, we also, I must say 50 percent of the temples have gone there. They are just rubble now. But, fortunately, the royal palace is still standing, except one tower, which is leaning and which we have to consolidate very quickly that it doesn't fall down.

JEFFREY BROWN: In the city, soldiers and volunteers worked to clear bricks and debris from a Hindu temple.

WOMAN: We love our temple very much, so look at now. I want to care about this. And I want to help this temple very carefully and then other temples.

JEFFREY BROWN: Since the earthquake, Manhart's team has been struggling to assess the damage to the country's many temples and historic sites. And there has been some good news.

The Lumbini Temple, for example, said to be the birthplace of the Buddha, was left unharmed. Nepal is home to four designated World Heritage Sites, two natural and two cultural. One site alone, the Kathmandu Valley, contains seven world-renowned groups of monuments and buildings. And tourism is vital to this poor country's economy.

DEBRA DIAMOND, Curator, South and Southeast Asian Art, Smithsonian's Freer and Sackler Galleries: It's the largest concentration of World Heritage Sites anywhere in the world, and absolutely unique in their style and in their mixture of Hindu and Buddhist and secular traditions.

JEFFREY BROWN: Debra Diamond is curator of South and Southeast Asian art at the Smithsonian's Freer and Sackler Galleries in Washington, itself home to a Nepalese bodhisattva.

DEBRA DIAMOND: Their bronze casters and woodcarvers were historically considered among the greatest artists of the region. And they not only worked in Nepal, but they were called to China. And they worked in Tibet. So, they were understood as really important.

JEFFREY BROWN: It's a fact not lost on locals. After early reports of looting, Manhart says citizens, police and the military have come together to protect the sites.

These are not just relics from a bygone era, he and others point out, but living history that people interact with on a daily basis. That was on display this week in the capital, where even amid the destruction and loss of life, the Nepalese celebrated the Buddha's birthday.

CHRISTIAN MANHART: When I arrived in Nepal, I was really struck by the spirituality of the people, by this living culture they still have. They go to the temple every morning to give some offerings. Each temple has its own festivals. And the people are very strongly connected, and it's part of their daily lives. And what is the danger of course, if the tangible heritage, so the temples, disappear, then there can also be intangible heritage will — will disappear.

JEFFREY BROWN: There are reasons for some hope. The way the temples and buildings were constructed, for example, should make them easier to rebuild.

DEBRA DIAMOND: Many of them are in this very distinctive Nepalese style that uses brick and wood. So we see these pagoda-like towers with many different roofs and struts that are made of carved wood. And when there's an earthquake, those buildings tend to fall straight down. And the struts survive and the bricks survive, so there's a lot that can be recycled.

CHRISTIAN MANHART: And, also, we have very detailed documentation. We have good photographs of the sites. We have architectural drawings and plans. We have measurements, so all this helps for future restoration.

JEFFREY BROWN: Manhart says that, with thousands of temples to restore, the work could take at least 10 years and perhaps decades, all part of a rebuilding effort throughout the country that by all accounts will require a huge international aid commitment.

For the PBS NewsHour, I'm Jeffrey Brown in Washington.