Humans have walked the Earth for 190,000 years, a mere blip in Earth's 4.5-billion-year history. Learn more about the planet's tumultuous past.
More About the Prehistoric World
National Geographic's interactive time line takes you on a 4.5-billion-year-old trip through Earth's history⎯from its Precambrian birth to the birth of Homo sapiens some 190,000 years ago.
The largest animals that ever flew, pterosaurs ruled the Mesozoic skies for 150 million years, flapping and soaring long before the first bird ruffled a single feather.
In the international fossil trade, even priceless specimens have a price tag. Ancient bones can end up in a movie star's mansion as easily as in a museum.
More than 90 percent of all organisms that have ever lived on Earth are extinct. Learn how millions of creatures can disappear in a geological blink of an eye—and see what might be next.
An affordable-housing advocacy group is building houses that will save homeowners hundreds of dollar in energy costs. Video.