https://www.bbc.com/news/av/world-middle-east-44824997/syria-war-rebels-underground-tunnel-network-in-douma This story along with many many others in the news about Syrian rebel tunnels. I see they are now carving art into the tunnels. Seems like art would be a clever way to cap a tunnel that you don't want people to find! Spider's web of tunnels. CERN boring machines. All 'roads' lead to Rome, Vatican and CERN