To orient ourselves, let us condense the full scope of human history into a single day beginning at the stroke of midnight. This moment marks the advent of toolmaking 3.3 million years ago (ma), which is considered the earliest known manifestation of human culture. It is not until 11:30 am the following morningthat the first members of our genus spread out of Africa, walking fully uprightand equipped with significantly bigger brains than their predecessors. At 9:43 pm in our metaphorical day, fossils bearing modern human features begin to appear in North Africa and Southwest Asia. The first modern humans in Arabia show up around 11:05 pm. By 11:47 pm, our species disperse across the globe, assimilating,displacing, and replacing all other human-like species with whom we came in contact.Along the way, our ancestor’s learned to navigate the open seas and began tocreate art and music. From 11:48 to 11:51 pm, early humans weathered the coldextremes of the last ice age. With 4 min left until midnight, some transitioned from hunter-gatherers to farmers and herders. At 11:58 pm, humans invented writing and began to document events and genealogies, coinciding with Year 1 of the Hebrew calendar called Anno Mundi. Year 1 of the Christian calendar, Anno Domini, was 53 s ago, while Year 1 of the Islamic calendar, Anno Hegirae, occurred 38 s ago. In this metaphorical day of humanity, only the last 2 min are recorded on paper, while the remaining 23 h and 58 min lie buried beneath the sands of time. This is what distinguishes history from prehistory.
