ventilation shaft
after our hot air balloon ride we visited the derinkuyu underground city, which was carved out of the soft volcanic rock. some of us went as far down as the eight level. this picture was taken up one of the ventilation shafts (the light at the end of the tunnel is the surface). i think i was on the third level for this one. it felt pretty cramped most of the time underground so it was hard to get many good pictures. they actually designed the underground cities to make it difficult for invaders to get in, with passageways only one person wide and less than a person tall, and stone doors that required two people from the downward side of the passage to open or close.