The Paris Gun (aka "Lange Max", "Big Bertha", "Kaiser Wilhelm Geschuetz") was a giant (40m barrelled), rail-mounted artillery gun used by the German's in WW1 to lob shells at Paris. The guns (of which seven were produced, although only two saw service) were able to lob a 120kg shell (containing 7kg of explosives) 131 miles. In flight the shells reached a maximum altitude of 40km - the highest altitude reached by a man-made object until the first launch of the V-2 rocket in 1942. In total, the guns lobbed 351 shells at Paris, killing 256 and wounding 620.

To aim the shells, the German's employed spies on the ground in Paris, who would report where each shell landed - the guns trajectory would be adjusted accordingly.

The Paris Guns were a military failure for several reasons: they could only shoot 65 shots before the barrels had to be replaced, the accuracy was only good enough for city-sized targets, and the explosive payload was tiny. As a terror weapon, however, it was a marked success. The Paris gun would be the inspiration for the V-series rockets employed, again by the German's, in WW2 - and later Gerald Bull and his Super Artillery.

Near the end of the war the guns were evacuated in the face of the allied advance, and besides a spare mounting captured by some American troops, none of the guns were ever captured by the allies.

Sources:

• http://www.friends-partners.org/mwade/lvs/parisgun.htm
• http://www.secretsofwar.com/html/super_guns.html
• http://www.probertencyclopaedia.com/F6.HTM