Underground City

Inside the underground city.  I have wanted to visit the underground city for a long time after hearing about them.  People must have been a lot shorter when they built these places.  I had to crawl on my hands and knees several places.  I had wondered about what happened to smoke from fires.  According to the guide the smoke would be absorbed by the rocks. When the rocks where black with soot they inhabitants would dig more of the soil out and remove it.  The guide said many of the underground cites are connected even 12 Kilometers away.  The air vents were small narrow wells going straight up and down but I am sure the very interconnectedness of the tunnels and rooms help air circulation. It appears the use of the cities was both for storage but also for defense from invaders.