When comets attack...

you better watch out, especially if the "Tunguska event" of 1908 is any indication. Here's a new twist to the long accepted idea that a fragment of a comet or asteroid exploded in the atmosphere over Siberia, leveling ~ 800 square-miles of forests, in what was the largest non-nuclear explosion in recent history.

Hint: a big part of the object still exists. Guess where it is?