The way through a wall. It lets your side and your allies pass, and shuts when anyone else comes near: enemy troops and workers, and bandits. It opens again a while after the last of them has gone.

Its stairs lead up to the wall walk, so a gatehouse is also how your troops get onto the wall.

A Battering Ram is the machine for breaking one.

Besides the game’s Closed and Automated, its panel has Auto open (the default, as above) and Force open, which lets everyone through, enemies too. Automated still shuts on enemies, so a Watchtower’s signal can close it before anyone gets near.

Over a ditch or a moat, the Drawbridge Gatehouse raises a bridge as it shuts.