After a brief charging period, the drone carrier's energy cannon attack officially began. Suddenly, eighteen gigantic energy beams appeared in space, which pierced the surface of the North American continent, destroying the underground rocks with unstoppable force and causing violent explosions deep underground.
During the Cold War, to guard against the enemy's nuclear missile attacks, the United States built its last intercontinental missile bases and nuclear weapon storage 2000 meters deep underground. At this depth, protected by solid rock layers, even if the surface faced enemy nuclear missile attacks and all ground structures were obliterated, the last intercontinental missiles and nuclear weapon storage could survive, enabling a nuclear counterattack against the enemy, leading to mutual destruction.
