What is mobilization?
After the discovery of Nationalism, you may elect to mobilize your economy for war. During a war-time economy, in any city building a military unit (but not a military improvement more on this below), each tile being worked by a citizen that already produces at least one shield will produce an extra shield,
During a war-time economy, your cities may only undertake building projects of military units or militaristic city improvements, with some limited exceptions (see below). Cities building non-militaristic units before the war-time mobilization may continue their non-military projects (without the shield bonus provided by mobilization), provided that, once such project is completed or is changed, the city will come under the same build restrictions as a city starting a project after the mobilization. Therefore, no new construction of temples, marketplaces, aqueducts, or a whole host of other city improvements is permitted after a mobilization. Also, during a war-time economy, each cultural improvement in each of your cities will generate only half of the cultural value it would normally produce. Finally, as noted more fully below, a war-time mobilization may not simply be abandoned by the player; a peace treaty must be signed with at least one AI civ (or an AI civ with whom you are at war must be destroyed) in order to return ones economy back to a peace-time.
