Guard Tower

The Guard Tower is the name of two completely different buildings for Age of Empires and Age of Empires II. In both cases it is a defensive structure costing a large amount of stone.

Age of Empires
In Age of Empires, the Watch Tower is the worst type of tower. It is available first on the Tool Age, after researching Watch Tower from the Granary. It offers effective defence against other Tool Age units, but needs to be upgraded to the Sentry Tower to have any kind of effectiveness against Bronze Age units.

Age of Empires II
In Age of Empires II, the Watch Tower is also the lowest type of tower, first available on the Feudal Age. Unlike in Age of Empires, no research is needed to be able to build one. They are weak, and are easily destroyed by foot units as they cannot attack units at minimum range. They can be upgraded to Guard Tower.