Listening Post (CTP1)

is a tile improvement in Civilization: Call to Power.
==Gameplay==
Listening posts are structures which one can build outside a city to increase the Civilization's range of vision and protect its borders. They use technology and reconnaissance to detect units over great distances. Each listening post has a vision range of eight. This installation costs 1,000 PW with a four turn build time.
==Great Library entry==
Listening posts developed as an early warning system along a border or hostile front. Early posts used nothing more than a trained ear or guard dogs to listen for the enemy when visible detection was not possible. Beginning with the 20th century, listening posts employed electronic microphones to detect even a single infiltrator making a midnight raid. Listening posts also served as a tool for border patrols to monitor illegal border crossings and drug smuggling.