We just learned about the Witch Tower.
Another type of fortification is Dragon's Teeth.
Much later than the old times of swords and arrows, one of the most powerful weapons in war was the tank.
Tanks were pretty much just armored cannons on wheels, and could not be destroyed by soldiers or simple guns.
So people made other ways to stop them, like putting giant spikes into the ground that tanks could not drive over.
(from: wikipedia - dragon's teeth (fortification))
Kid Facts - Blast from the past: Bellver Castle
