The History of the Earth
A breakdown of the four Geologic Eras can be found here.
Below is the full Geologic Time Scale, courtesy of the Geological Society of America. Compare the 2009 scale to the 1983 scale. Why do you think these changes needed to be made?
Evidence shows that dinosaurs died 65 million years ago. If you look at the Geologic Time Scale, you will see that corresponds to the split between the Mesozoic and the Cenozoic Eras, specifically between the Cretaceous period and the Tertiary Period. The below video is about scientists following a trail of evidence that explained what might have happened 65,000,000 years ago. You can learn more about this here.