The continuous development of ancient human activities at hundreds of locations in the Paleolithic Age (2,000,000 to 10,000 years ago), as represented by sites like the Luanchuan ape-man site, the Nanzhao ape-man site and the Xuchang man site, as well as the Zhijidong site in Xingyang, and the Laonainaimiao site at the northern foot of the Songshan Mountains, are testament to the independent origin and uninterrupted evolution of ancient humans in the Central Plain. The density of sites of ancient human activity since the late Paleolithic Age discovered along the Songshan Mountains, the Lijiagou site bridging the Paleolithic culture and the Neolithic culture, and the subsequent evolution of human settlements in the Songshan Mountains in the Neolithic Age into the early states, have ensured the core position of the Songshan Mountains as "the Center under Heaven".