2.2 The Works of Man

Settlers and Engineers are able to change the face of the Earth, as has been noted earlier. Engineers are more advanced Settlers, able to do the same things more quickly, and capable of new feats; the previous terrain table shows the transformations that Engineers can perform.

Deserts, Plains, Grasslands, Hills, and Rivers may be irrigated, if there is a nearby source of water (a square immediately to the north, south, east, or west, which is a Ocean, River, or already irrigated). Irrigating a square causes it to produce one more food point per turn.

Forests, Jungles, and Swamps may be cleared by the "irrigate" order, converting them to Plains, Grasslands, or Grasslands, respectively. Clearing does not require a source of water.

Deserts, Hills, and Mountains may be mined. Mining a Desert or Mountain square causes it to yield 1 extra production point per turn; mining a Hill produces 3 extra production points (reflecting the increased accessibility of hillside mines and trails). Grassland, Jungle, Plains, and Swamp squares may be forested by the "mine" order, converting each of them into a Forest.

Irrigating or clearing a square removes any mine in that square, and mining or foresting a square removes any irrigation in that square.

Roads and railroads may be built on any square except Ocean. (To build either on a River square requires the advancement Bridge Building; to build Railroad requires the advancement Railroad.) A Settler or Engineer can be orders to build a road on land with none, or a railroad over an existing road.

• Roads allow land units to move at one-third of a movement point per square when moving from one road square to another, regardless of the movement cost of the underlying terrain. Roads in Desert, Grassland, and Plains squares cause them to produce one additional trade point.
• Railroads allow land units to move from one railroad square to another at no movement cost at all. Railroads increase the production points of a square by 50%. (Server options exist to modify this bonus, and apply such bonuses to food and trade as well.)

Settlers and Engineers may also construct a Fortress in a land square (if the advancement construction is known), which may exist in addition to any other features of the square. A Fortress gives aid to defending units (see Combat), and influences city morale for units in the Fortress (see Cities).

In addition to constructions placed by the civilizations, the map also contains tiny Villages, representing small cultures not destined to become major civilizations. When a land unit of a civilization enters a Village, the Village disappears, but its contents become revealed. Some contain gold, which goes into your treasury; others provide you with technological advances previously unknown to you. Some yield military or Settler units that freely join your empire, or become new cities in your empire. Lastly, some destroy your intruding unit instantly.

When you have a sufficiently industrialized and populous civilization, pollution can appear near your cities. Pollution appears based on the production points and population of your cities. Pollution can also be caused by Nuclear weapons. When a square becomes polluted, this symbol appears; see Population for the effects of pollution. Settlers and Engineers need to be assigned to clean up pollution, to return land squares to productivity, and to prevent global warming.