Since the 1930’s, archaeologists have tunneled into the acropolis at Copan to understand the many phases of construction throughout its history. With investigations now mostly complete, the tunnels measure close to 4 kilometers in cumulative length, and have uncovered early stelae, plaster facades and tombs that have taught us much about what the acropolis was like before its final phase. A Harvard-led conservation plan in on-going collaboration with the Instituto Hondureño de Antropología e Historia for these tunnels created a digital 3D model of the tunnel system and addresses ways to preserve the valuable architectural heritage within, taking into account the humid climate, seasonal changes to the water table, visitor access, and risk of collapse. U