Pentagon helipad clock
This Skilcraft electric wall clock, which hung in the Pentagon helipad fire station, was knocked to the ground by the impact of American Airlines flight 77 crashing into the Pentagon. Context:
When terrorists flew American Airlines flight 77 into the Pentagon, the crash nearly took the nearby Pentagon helipad firehouse with it. The concussion caused the ceiling of the firehouse to collapse, temporarily trapping firefighter Dennis Young in the fallen debris. The blast also knocked this clock from the wall, freezing it at 9:32. The airplane actually struck the Pentagon at 9:38 am; apparently the clock was six minutes slow.