Armories are special buildings that hold ADU technology and weapons in reserve.
Armories were covertly constructed when the ADU was being formed. They were constructed one after the other, as to not arouse suspicion. Tunnels were dug to connect the assorted armories, with explosives installed in the armories and tunnels in case they fell into enemy hands.
Twenty-four armories had been built in Lego City by the alien invasion, each named after a letter of the Greek alphabet. Armory Alpha was also the headquarters of the ADU forces. Twelve armories were disbanded, to reinforce the other twelve.
Disguised as assorted buildings, such as warehouses, office buildings, factories, and even resturants, the armories were made of concrete bunkers buried deep underground, with entrances to the building above. The resturants actually were in business to keep up appearances, but the majority didn't serve in their disguise's capacity. They were equipped with lots of security cameras and motion sensors to detect if intruders were nearby. Missile racks, turrret-mounted guns, and only on Armory Alpha, laser weapons, made up the automated defenses.