Prehistoric time line, geologic time scale, photos, facts, maps, and more from National Geographic. Humans have walked the Earth for 190,000 years, a mere blip in Earth's 4.5-billion-year history.

That person was Karen Wynn Fonstad, and in 1977, this part-time ... over its 175-year history. Now in its 32nd printing, Fonstad’s Atlas Of Middle-earth featured 182 hand-drawn maps and included ...

Archeologists have discovered evidence of a previously unknown prehistoric civilization ... hiding in plain sight, Google Earth helped researchers find over 100 locations, he said.