The Blackhawk Island.
Blackhawk Island was the base of operations for the World War II military air unit, the Blackhawks.
The island contained the Blackhawks' airbase.
The Blackhawks kept a secret armory of captured weaponry, some of which were incorporated into the island's defense systems.
Lex Luthor, The Key, and Dr. Polaris broke into the armory and stole the Spear of Longinus.