During the 40th century BC, the Near East and southeastern Europe were in the Chalcolithic period (Copper Age), transitional between the Stone and the Bronze Ages. Northwestern Europe was in the Neolithic. China was dominated by the Neolithic Yangshao culture. The Americas were in a phase of transition between the Paleo-Indian (Lithic) to the Meso-Indian (Archaic) stage. Started in 4000 BC and ended in 3901 BC.
The fourth millennium of the Gregorian calendar will begin on January 1, 3001, and end on December 31, 4000. It will be the fourth millennium in the Anno Domini or Common Era.