'Asteroid Day' is a good time to learn about the threat of space rocks
 

On June 30th, 1908 more than 770 square miles of remote Russian forest were obliterated from the face of the Earth when a relatively small meteor, only around 400 feet across it's estimated, unleashed 15 megatons of energy above the Stony Tunguska Ri...

https://www.engadget.com/2017/06/30/...e-rock-threat/