Trial Attack on US Power Grid?

[CharlesHarris]

The largest conventional bomb used by the Allies during WW2 was the Grand Slam, a 22,000 pounder which after release from the Avro Lancaster B. Mk 1 2 would approach 320 m/s, 715 mph terminal velocity before impact, penetrating deep underground before detonating. The resulting explosion could cause the formation of a camouflet (cavern) and shift the ground to undermine a target's foundation. Grand Slam was originally designed to penetrate concrete roofs and was more effective against hardened targets than any existing bomb.

By the end of the war, 42 Grand Slams had been dropped on active service.

Five complete Grand Slam bombs are preserved and displayed in the United Kingdom at the RAF Museum, London; Brooklands Museum; RAF Lossiemouth; Dumfries and Galloway Aviation Museum and the Battle of Britain Memorial Flight Visitors' Centre at RAF Coningsby. Main portions of these bombs, without their lightweight tails, can be seen at the Kelham Island Museum in Sheffield and Yorkshire Air Museum at Elvington.

A T-14 bomb (American-made variant) is displayed at the Air Force Armament Museum at Wright-Patterson AFB in the United States.