During the Pascal-B nuclear test of August 1957, a 900-kilogram (2,000 lb) iron lid was welded over the borehole to contain the nuclear blast, despite Brownlee predicting that it would not work. When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere at a speed of more than 66 km/s (41 mi/s; 240,000 km/h; 150,000 mph). The plate was never found. Scientists believe compression heating caused the cap to vaporize as it sped through the atmosphere.

A one ton iron vent cap (sewer plate) moved so fast it vaporized. Iron into gas, just add velocity in atmo. That's so fucking cool.