Castle Rock is a huge rock boulder that is attached to the rest of the island by a narrow rock bridge which is located well below the level top of the rock, as described in chapter 6. Jack notes in this chapter that the rock would make a great fort. In chapter 11, Ralph and Piggy, in an attempt to get back Piggy's glasses, approach Jack and his tribe who now have their fort on Castle Rock. Roger has a large rock poised on the edge of the top of Castle Rock. He has a lever wedged underneath it and the rock is set in such a way that, when it is pushed by the lever, it will fall onto the rock bridge below. Since the rock bridge is the only way to get to Castle Rock, this makes the rock a perfect weapon to use against an enemy. Also, since the top of Castle Rock is high above the surrounding area, it is easy to see anyone advancing.