Explorer Albert Lin descends into an epic underground cavern

Explorer Albert Lin descends into the underground world of Seventh Hole. National Geographic Explorer Albert Lin is on an extraordinary mission to unlock the secrets of our lost cities. Using cutting edge technology to strip back the layers of time, Albert pushes himself and his team to the edge in some of the most remote and hostile environments on earth. Want to see more? Watch the full episode right here on Disney Enjoy a free trial of National Geographic right here: ➡ Subscribe: ➡ Watch all clips of Lost Cities with Albert Lin: And check out more National Geographic series and specials here: ➡ D