From Rick Pettigrew comes this:

Friends and colleagues: The catacombs of Rome, underground cemeteries where early Christians took refuge, played an important role in the development of modern archaeology.  See how that took place in The Witnesses of Silence: Discovering Rome's Catacombs, the latest video feature on our nonprofit streaming-media Web site, The Archaeology Channel (http://www.archaeologychannel.org).
 
This film retraces the rediscovery of the catacombs, subterranean burial places and hideouts beneath the streets of ancient Rome.  It finds in the dark galleries the traces of early explorers and the signatures, graffiti and inscriptions they left.  These early underground explorers include legendary figures such as Antonio Bosio and Giovanni Battista de Rossi, the scholar who laid the scientific basis of modern Italian archaeology.  This film sheds new light on an underground world where silence dominates but images retell stories voiced many centuries ago.