However, Google Earth has the next best thing for thehistory nerds: a feature called Historical Imagery that allows you to ...

The Eastern State Penitentiary offers both self-guided (with audio) and guide-led tours during the day. You can also take a nighttime tour (6 to 10 p.m., Thursday through Sunday) in the summer months.

Scientists working to understand this event, which caused the biggest mass extinction in Earth’s history, warn that a similar story may unfold if we continue emitting greenhouse gases.