Who was the first person to build an under ground cave

Ancient piles of broken stalagmites found deep inside a cave in France were made by Neanderthals about 176,000 years ago, way before modern humans were around. This is the first time archaeologists have concluded that our cousins ventured underground and built complex constructions.

answer; i believe the answer is (mesopotamia); modern day

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.