California Highway One, between Pacifica and Montara, was carved out of the steep coastal cliffs. Plagued by closures due to rockslides and land slippage, this route has earned the nickname "The Devil's Slide." Now two tunnels beneath San Pedro Mountain, each 30-feet wide and 4,200-feet long are being dug to bypass it. QUEST meets the engineers and geologists deep underground to learn how Caltrans is digging this new tunnel.