I’m only a few meters from the entrance where a little bit of daylight spills in, and already it’s completely dark when I turn off my flashlight, I literally cannot see my hand in front of my face. I am truly in the underground, where human eyes cannot penetrate the darkness no matter how used they get to it. I don’t dare to go further in because there are no lights to guide the way and getting lost down in some old tunnels from the Vietnamese war is not a particularly appealing prospect. Instead I just stand here for a moment and savor the feeling.