Terrain	Natural Resources,      Food, & Trade	Movement Cost	Defense Bonus	Resources & Food with Improvements	Trade with Road
Arctic	None	2	+0% (or +100% with a fortress)	None can be built on this terrain	Road does not affect trade on this terrain
Coal (Hills)		2	+100% (or +300% with a fortress)	Irrigation	Road does not affect trade on this terrain
				Mine (Anarchy & Despotism)
				Mine (all other governments)
Desert		1	+0% (or +100% with a fortress)	Irrigation	Road (Republic & Democracy)
				Mine	Road (All other governments)
Fish (Ocean)	(Anarchy & Despotism)	1	+0% (No fortress can be built on this terrain)	None can be built on this terrain	Road (Republic & Democracy)
	(Monarchy & Communism)
					Road (All other governments)
	(Republic & Democracy)
Forest		2	+50% (or +200% with a fortress)	Becomes Plains when Irrigated	Road does not affect trade on this terrain
Game (Forest)	(Anarchy & Despotism)	2	+50% (or +200% with a fortress)	Becomes Horses (Plains) when Irrigated	Road does not affect trade on this terrain
	(All other governments)
Game (Tundra)	(Anarchy & Despotism)	1	+0% (or +100% with a fortress)	None can be built on this terrain	Road does not affect trade on this terrain
	(All other governments)
Gems (Jungle)	(Anarchy & Despotism)	2	+50% (or +200% with a fortress)	Becomes Grasslands when Irrigated	Road does not affect trade on this terrain
	(Monarchy & Communism)
				Becomes Forest when Mined
	(Republic & Democracy)
Gold (Mountains)	(Anarchy & Despotism)	3	+200% (or +500% with a fortress)	Mine	Road does not affect trade on this terrain
	(Monarchy & Communism)
	(Republic & Democracy)
Grasslands		1	+0% (or +100% with a fortress)	Irrigation does not effect food on this terrain with Anarchy or Despotism	Road (Republic & Democracy)
				Irrigation (All other goverments)
					Road (All other governments)
				Becomes Forest when Mined
Grasslands II		1	+0% (or +100% with a fortress)	Irrigation (Anarchy & Despotism) Has no effect	Road (Republic & Democracy)
				Irrigation (All other goverments)
					Road (All other governments)
				Becomes Forest when Mined
Hills		2	+100% (or +300% with a fortress)	Irrigation	Road does not affect trade on this terrain
				Mine (Anarchy & Despotism)
				Mine (All other governments)
Horses (Plains)		1	+0% (or +100% with a fortress)	Irrigation	Road (Republic & Democracy)
				Becomes Game (Forest) when Mined	Road (All other goverments)
Jungle		2	+50% (or +200% with a fortress)	Becomes Grasslands when Irrigated	Road does not affect trade on this terrain
				Becomes Forest when Mined
Mountains		3	+200% (or +500% with a fortress)	Mine	Road does not affect trade on this terrain
Oasis (Desert)	(Anarchy & Despotism)	1	+0% (or +100% with a fortress)	Irrigation (Anarchy & Despotism)	Road (Republic & Democracy)
				Irrigation (All other governments)
	(All other governments)			Mine (Anarchy & Despotism)	Road (All other governments)
				Mine (All other governments)
Ocean	(Republic & Democracy)	1	+0% (No fortress can be built on this terrain)	None can be built on this terrain	Road (Republic & Democracy)
	(All other governments)				Road (All other governments)
Oil (Swamp)		2	+50% (or +200% with a fortress)	Becomes Grasslands when Irrigated	Road does not affect trade on this terrain
				Becomes Forest when Mined
Plains		1	+0% (or +100% with a fortress)	Irrigation	Road (Republic & Democracy)
				Becomes Forest when Mined	Road (All other goverments)
River	(Republic & Democracy)	1	+50% (or +200% with a fortress)	Irrigation does not affect food on this terrain with Anarchy or Despotism	Road does not affect trade on this terrain Additionally, Bridge Building is required to build roads on this terrain
				Irrigation (Monarchy & Communism)
	(All other governments)
				Irrigation (Republic & Democracy)
River II	(Republic & Democracy)	1	+50% (or +200% with a fortress)	Irrigation does not affect food on this terrain with Anarchy or Despotism	Road does not affect trade on this terrain Additionally, Bridge Building is required to build roads on this terrain
				Irrigation (Monarchy & Communism)
	(All other governments)
				Irrigation (Republic & Democracy)
Seals (Arctic)		2	+0% (or +100% with a fortress)	None can be built on this terrain	Road does not affect trade on this terrain
Swamp		2	+50% (or +200% with a fortress)	Becomes Grasslands when Irrigated	Road does not affect trade on this terrain
				Becomes Forest when Mined
Tundra		1	+0% (or +100% with a fortress)	None can be built on this terrain	Road does not affect trade on this terrain

Irrigation When the early farmers moved down from the hills into the valleys of the Nile, Tigris, and Euphrates Rivers, they had to develop the technology of irrigation. The freshwater rivers passed through lands essentially barren due to the lack of rainfall. Through irrigation, water could be removed from the rivers and spread on the nearby land, making it bloom. Ever since these early days, irrigation has been an important tool of farmers, making other deserts bloom as well. Modern examples are the very productive deserts of California. Irrigation increases the food value of River, Grassland, Plains, Desert, and Hill squares. Only squares vertically or horizontally adjacent to water (Ocean or River) or existing irrigation squares may be irrigated.

MINING When thinking humans first evolved, it was possible to find nearly pure deposits of several metals exposed on the Earths surface. The most common were gold, silver, and copper. As time passed, the surface deposits were exhausted and men began digging into the ground looking for more. The mining and excavation of the Earth in search of minerals continues today, although the list of things for which we dig has greatly expanded. The discovery of new metals and resources, or new methods of extraction, often turned previously unwanted areas into mother lodes of oil, uranium, platinum, etc. Mining increases the production value of Desert (+1), Hills (+3), and Mountain (+1) squares.

RAILROADS Railroads revolutionized transportation by providing a relatively cheap and fast method of moving people, raw materials, finished goods, and military units. Railroads were essential to the Industrial Revolution. Not only did they support and encourage industrial growth by dramatically reducing transport costs, but they spurred technological research on their own. Advances in locomotive technology and engineering spun off into other industries and applications. Railroads were the first great industrial corporations. Built by Settlers only, and only in squares that already contain a road. Press the Railroad key (R key). Units moving from one railroad square to another railroad square use no movement points regardless of terrain. Railroads increase food and resource production in a map square by 1/2 (rounded down). They increase trade by the same amount, but before the effects of Republic or Democracy governments.

ROADS Roads of good quality improved communications between cities. This was important for trade and for military purposes. Good quality roads were passable in nearly all weather, and could be traversed by wheeled vehicles much faster than bare dirt trails. This meant that mounted messengers, commercial wagons, and military units all could move from one part of the road network to another at good speed. This made it easier for centrally located armies to reach threatened frontiers. The most famous roads of antiquity were the Persian Royal Road and the Roman roads built throughout southern Europe. Built by Settlers only. Press the Road key (R key) or select Build Road from the Orders menu. Roads may not be built over Rivers until you have acquired Bridge Building. Units moving from one road square to another road square use 1/3 of a movement point regardless of terrain. Roads increase the trade generated by Grasslands, Plains, and Deserts.

POLLUTION Pollution may be caused by large resource production in cities, large city populations, nuclear weapons, or the meltdown of a Nuclear Power Plant. If a city has a potential pollution problem, smokestacks in the city display information window indicate the probability that a nearby map square may become polluted. The pollution in a map square may be cleaned up by a Settler. Move the Settler into the square and press the Pollution key (P key) or choose the Pollution option from the Orders menu. It takes four turns of work to clean up pollution. If pollution gets out of control, global warming may occur.