During World War II, various nations built extensive defenses to protect their territories from enemy attacks. These included fortified bunkers, trenches, and coastal defenses, which were designed to withstand bombings and ground assaults. Countries like France constructed the Maginot Line, a series of fortifications along their eastern border, while Britain developed radar systems to detect incoming enemy aircraft. Naval defenses also played a crucial role, with nations deploying aircraft carriers, submarines, and destroyers to secure their waters. The use of anti-aircraft guns and barbed wire further enhanced protection against aerial and ground invasions. These strategic measures were vital in shaping the outcomes of battles throughout the war.