We just learned about the Castle Keep.
Another part of a castle is a Drawbridge.
This is a type of bridge that goes across a moat, that can be pulled up to keep people from getting into the castle.
Drawbridges are still used today for bridges that go across rivers or lakes.
There are a few different types of drawbridges, like a bascule bridge that has two ends that lift up in the middle, a vertical lift bridge that has one piece that goes up and down together, or a swing bridge that spins in the middle.
(from: wikipedia - drawbridge)
Kid Facts - Blast from the past: Citadel of Aleppo
