Secrets of the Underground (2017)

Using cutting-edge technologies such as ground penetrating radar (GPR), LIDAR (Light Detection and Ranging), and 3-D imaging, scientists research fascinating underworlds of secret tunnel networks, ancient structures, and bizarre geological occurrences that offer glimpses into our history.

Genres: Documentary

Actors: Rob Nelson，Stefan Burns，Tim Bechtel，Adam Cho，Jared Peacock，Valerie Van Heest，Tracy Beach，Bradley T. Lepper，Brent Breithaupt，Griffin Alberti，Janet Watt，Jennifer Burnham，Larry Johnson，Tim Kilgannon，Aubri Jenson，Luther Strayer，Dale Rucker，Frank Watson