By: The Marlboro Man. Read more... The V-3 (Vergeltungswaffe 3), also known as the Hochdruckpumpe ("High Pressure Pump", HDP for short) and Fleissiges Lieschen ("Busy Lizzie"), was a German World War II supergun working on the multi-charge principle whereby secondary charges are detonated to add velocity to a projectile.
The weapon was planned to be used to bombard London from two large bunkers in the Pas-de-Calais region of northern France, which were rendered unusable by Allied bombing raids before completion. Two similar guns were used to bombard the city of Luxembourg from December 1944 to February 1945.