A close-up shows detail of a dagger dating from the first century A.D. The knife will go on display in a new U.S. exhibition of Afghan treasures in 2008.

The dagger was found at the archaeological site of Tilly Tepe, in northern Afghanistan, where the graves of six ancient nomads were discovered in 1978.

The far-flung origins of the exhibition's pieces show Afghanistan's role as a cultural hub in the set of trade routes known as the Silk Road during the first century B.C, according to archaeologist Fredrik T. Hiebert, a National Geographic Committee for Research and Exploration grantee.

Hiebert helped inventory the objects and is curating the U.S. exhibition.

"This exhibition is really about heroism," Hiebert told National Geographic News.

"These pieces should not be around today. They are here because people risked their lives to safeguard them."

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