The End-Cretaceous (K-Pg) Extinction: The Final Curtain Around 66 million years ago, Earth endured a mass extinction event that marked the end of the Cretaceous and the start of the Paleogene period.

A newly described dinosaur that appears to have persisted beyond a catastrophic die-off is forcing scientists to rethink how mass extinctions actually play out on the ground. Instead of a clean break ...

For most of human history, extinction has been understood as an immutable fact of nature—a one-way door that, once closed, could never be reopened. Species disappear, their genetic innovations vanish ...