The 2nd millennium BC spanned the years 2000 BC to 1001 BC. In the Ancient Near East, it marks the transition from the Middle to the Late Bronze Age. The Ancient Near Eastern cultures are well within the historical era: The first half of the millennium is dominated by the Middle Kingdom of Egypt and Babylonia. The alphabet develops. At the center of the millennium, a new order emerges with Mycenaean Greek dominance of the Aegean and the rise of the Hittite Empire. The end of the millennium sees the Bronze Age collapse and the transition to the Iron Age. Other regions of the world are still in the prehistoric period. In Europe, the Beaker culture introduces the Bronze Age, presumably associated with Indo-European expansion. The Indo-Iranian expansion reaches the Iranian plateau and onto the Indian subcontinent (Vedic India), propagating the use of the chariot. Mesoamerica enters the Pre-Classic (Olmec) period. North America is in the late Archaic stage. In Maritime Southeast Asia, the Austronesian expansion reaches Micronesia. In Sub-Saharan Africa, the Bantu expansion begins. World population rose steadily, possibly surpassing the 100 million mark for the first time. The world in the 2nd millennium BC History See the article on chronology of the ancient Near East for a discussion regarding the accuracy and resolution of dates for events of the 2nd millennium BC in the Near East. Middle Bronze Age Spending much of their energies in trying to recuperate from the chaotic situation that existed at the turn of the millennium, the most powerful civilizations of the time, Egypt and Mesopotamia, turned their attention to more modest goals. The Pharaohs of the Middle Kingdom of Egypt and their contemporary Kings of Babylon, of Amorite origin, brought good governance without much tyranny, and favoured elegant art and architecture. Farther east, the Indus Valley civilization was in a period of decline, possibly as a result of intense, ruinous flooding. Egypt and Babylonia's military tactics were still based on foot soldiers transporting their equipment on donkeys. Combined with a weak economy and difficulty in maintaining order, this was a fragile situation that crumbled under the pressure of external forces they could not oppose. Unrest of the 16th century About a century before the middle of the millennium, bands of Indo-European invaders came from the Central Asian plains and swept through Western Asia and Northeast Africa. They were riding fast two-wheeled chariots powered