In 1944 during World War II, US and British engineers built a massive floating harbor. When soldiers from these countries landed in France to fight the Germans, ships towed the harbor to the French coast. Within days it was working to bring supplies to the soldiers. Engineering has always been an important part of war. Engineers have built defenses to protect soldiers, as well as roads and ships to move troops quickly. Engineers constructed huge castles—and also made giant catapults and battering rams capable of destroying castle walls. From the helicopter to the hovercraft, discover how military engineers have changed war on land, at sea, and in the air!