These giant rocks could roll at any moment. The fact they haven't offers a window into the shaking of ancient Earth.

Precariously balanced rocks, or PBRs, record a history of things that haven't happened We've all seen them; we've even taken pictures of ourselves pretending to hold them up or to push them over.

A chilling new report from the world’s top climate scientists has delivered a stark warning, Earth's "vital signs" have reached a breaking point, with the future of humanity precariously hanging ...