On this date in 2004, Marvin Heemeyer used a bulldozer he modified himself to enact a rampage of revenge against the town of Granby, Colorado, for what he saw as extortionate requirements to improve a piece of property he had bought, followed by the approval of construction for a concrete plant adjacent to the property. The destruction ended with his death by suicide after the Killdozer began to break down.

The bulldozer was a modified Komatsu D355A, which he referred to as the “MK Tank” (or “Marv’s Komatsu Tank”) in audio recordings, fitted with makeshift composite armor plating covering the cabin, engine, and parts of the tracks. Three external explosions and more than 200 rounds of ammunition fired at the bulldozer had no effect on it.