Not all cosmic impacts leave craters. An iron asteroid 150 feet wide slammed into Arizona and carved out Meteor Crater, a hole 600 feet deep and over half a mile across. But at Tunguska in 1908, a fragment roughly the same size, likely from a comet, exploded five miles up and flattened 800 square miles of forest without leaving a crater at all. After a few centuries, the forest regrows and the evidence fades. The difference comes down to density and composition: dense iron punches through the atmosphere and hits the ground, while lower-density cometary material detonates in the air. The evidence suggests airbursts may be ten times more common than ground impacts, yet they leave far less permanent trace in the geological record. If that ratio holds, how many catastrophic events have we missed simply because they didn't leave a hole?