7066 Earth Defense HQ is an Alien Conquest set released in May of 2011. It is the largest and most expensive set in the theme, containing 874 pieces. It consists of a large wheeled vehicle (the Earth Defense HQ), a jet, a small flying saucer, and a small wheeled vehicle, as well as five minifigures (the ADU Soldier, ADU Scientist, Alien Cyborg, Alien Trooper, and Alien Clinger) three of which (the ADU Soldier, ADU Scientist, and Alien Cyborg), are exclusive.