Explore 25 Major Events in Earth's 4.5 Billion Year History. Discover pivotal moments from its formation to the rise of life.

3. 25 Facts About Geologic Time That Made Our Brains Hurt 4. How Do We Know? A Glimpse into Geologic Sleuthing 5. Our Fleeting Moment in Deep Time 6. Frequently Asked Questions What if we told you ...

Our species likes it cold. Homo sapiens evolved in — and still inhabits — one of Earth’s rare and fragile ice ages, periods distinguished not by an abundance of saber-toothed cats and woolly mammoths ...