"That's exactly what happened! I was just a kid but ... "Sometimes I wonder if mankind had to live ‘underground’ due to something like a nearby supernova.
Put Gobekli complex was buried on purpose ... why have such a complex arrangement of structures then cover it with sand and abandon it?
"That's exactly what happened! I was just a kid but ... "For underground dwellings check this out http://en.wikipedia.org/wiki/Derinkuyu_Underground_City