Radar Towers provide a combat bonus to units within their affected area. To construct a Radar Tower, move a worker to any land tile within your territory and select the "Build Radar Tower" unit action. Construction of the Radar Tower consumes the worker. The range of the effected area is 2 tiles. Friendly units within the Radar Towers range get a +25% attack and defense bonus. This bonus can only be applied once, even if multiple towers overlap. Radar Towers can only be used by the player who created them. Should a Radar Tower fall into the territory of another civilization, it will be destroyed. Radar Towers can only be built in tiles that are empty or have a mine, irrigation, road and/or railroad. The "Build Radar Tower" unit-action becomes available after the Radio advance is researched.