Fortification is an upgrade in Age of Empires for Medium Walls which increases hit points by 100. It can be upgraded at Granary once Iron Age is reached. Like all buildings, its hit points increases, totaling up to 480 and build time is reduced when Architecture is researched.
- Babylonian and Shang fortifications have twice as much hit points, with a maximum hit points of 960. Thus, Babylonian and Shang fortifications have the highest building hit points before the introduction of Zenobia's Tower in The Rise of Rome.
- Fortifications are not available for Carthaginians, Macedonians, Minoans and Yamato.