Chapter 1548 - Fortress vs Fortress (4)

After World War II and the Day of Atonement War, permanent fortifications like fortresses and defense lines were once declared obsolete, their irrelevance seemingly confirmed by the poor performance of the "Saddam Defense Line" during the Gulf War, wherein people judged that permanent fortifications were no longer necessary after the unprecedented development of aerial power and technological weaponry. Some of the few remaining structures were revamped, such as the North American Air Defense Command buried beneath the Cheyenne Mountains during the Cold War, nuclear strike bunkers, and submarine caverns hidden in the shadows of islands and fjords—they all could be seen as a conceptual extension of fortresses in the new era. Arriving in the space age, the concept evolved to converting resource-depleted mining asteroids into fortress bases capable of docking fleets, becoming unshakeable battleships that guard the great routes through the seas of stars.