When does an archaeological dig happen?

It is an area which is slowly, carefully and methodically excavated under the supervision of one or more archaeologists. The goal is to find and preserve historical evidence of former inhabitants, societies and civilizations. Most areas of the Earth are slowly covered over by accumulated soil, so that it is necessary to dig down to find really old artifacts. An archaeologist is a scientist and historian who is trained in the location and interpretation of evidence confirming former human habitation.