With two others I have just entered a part of the Cu Chi Tunnel system that has remained pretty much the same way it was from it's origination.
Once a cover that hides the entrance to the tunnel is closed behind us we are pitched into complete darkness that is darker than a moonless night. It is only out of sense of being “macho” and having others with me that I am able to suppress some of my rising fear.
Following the light of an iPhone, it is a crawl on hands and knees over wet leaves as we navigate towards a promised exit. At one point our leader turns a corner and we are again pitched into complete darkness. His words in the distance that he can see the exit is comforting and I begin to slow my breathing.
Although we have only traveled about fifty feet or so it is not something I would want to do on any regular basis except if my freedom and life depended on it.