"I think the Oldowan technology is probably the most important technological innovation that ever happened in human history." ...

Flake scars: The mark that is left when a flake has been detached from a stone tool or core. Knife: A type of blade where the working edge is curved or serrated. Mt. Edziza: A volcano in northwestern ...

The Oldowan stone tools from Hadar, Ethiopia, are among the oldest known, dating back 2.3 million years. Shown from various angles are (a) two sharp-edged flakes and (b) a hand-held chopper.