A hundred years ago a large meteor exploded ten kilometers above the Earth's surface in Tunguska, obliterating 830 square miles of woods. It was the largest impact in recent history, but nothing compared to this.
The meteor-or comet fragment-was only a few tens of meters in diameter, according to modern estimates based on its 15 megatons energy blast. This 3D simulation, however,
shows what something like Apophis truly gigantic could do if it hits Earth. I saw it a while ago on the web, but now it is available in glorious HD, so you can see all the gritty-nitty detail of good old planet Earth getting completely obliterated.