In fact, not only the big ones, but even more recent smaller ones appear to be the results of multiple objects - even tens of thousands per event! Click the title for more.

Signs of the Times reports that governments don't want to increase spending on NEO tech/programs because it would cost more than the damage that might be done by an object exploding/impacting. The real frequency of atmospheric explosions and meteor impacts is much higher than is reported. Surprised? Even if you aren't, click the title for more.