Stone Age in Azerbaijan is divided into the Paleolithic, Mesolithic, and Neolithic periods. It was studied in Karabakh, Gazakh, Lerik, Gobustan, and Nakhchivan. Stone materials belonging to the Stone Age were found by Mammadali Huseynov in the Shorsu gorge located near the village of Gyrag Kasaman in Qazakh region. According to his research, people have first settled in the territory of Azerbaijan 2 million years ago. The Stone Age era involved two different human species: Homo neanderthalensis and Homo sapiens.[1][2][3][4][5]