Swipe Down for Full Video Story For more than 66 million years, Earth has been living through a remarkable chapter of history known as the Cenozoic Era. This enormous stretch of time transformed the ...

First, what is an ice age? It’s when the Earth has cold temperatures for a long time – millions to tens of millions of years – that lead to ice sheets and glaciers covering large areas of its surface.

Throughout much of Earth's history, the climate has switched between periods of extreme heat and freezing cold. Cold, glacial periods are characterized by large ice sheets in the Northern Hemisphere, ...

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. How many ice ages has the Earth had, and could ...