The Siege Factory is a military building, where siege/artillery units and Supply Wagons are built. It becomes available in the Classical Age, once File:Military Research Icon.png Military Level 2 (Mercenaries) is researched. It requires both Timber and Metal to be constructed. Types of units built at the Factory: * Artillery Weapons * Supply Wagon Being a military structure, it may be built anywhere within friendly (own or allied) borders. The ramping cost is doubled for every three buildings of the same type, whether existing or under construction.