A team of engineers spent years giving new life to old NASA tapes.
Scientists find the signatures of war on the edge of space.
Artifacts suggest that an extinct human species left Africa about 250,000 years earlier than previously thought.
When the bison were exterminated from North America, indigenous populations lost an inch of height in just a generation.
An exceptionally strong El Niño may have caused 1876-1878 famine that killed tens of millions.