If you build walls under the castle to keep out the mines; and walls above the castle to keep out the giants and flying creatures, then you might have a safe castle. Except for Magic. And running out of food.
They're out of arrows men, they're out of boiling oil. They've used the molten lead, and the baked sand and the furniture. They've nothing left to defend themselves with! So, up, my lads, and today Faenasti will be ours!
— Count Rudolf von Alptraum at the siege of Faenasti in the Border Princes during the War of the Barrel 2319-20. The Count was killed, when the defenders of Faenasti levered part of the wall onto his head., Warhammer