Civilization 3

Reveal entire map and resources:
Save the game. Include the word multi in the saved game name. Load the game you just saved. You now can now see the entire map and all resources.
Information in this section was contributed by brackencave.

Hint: Easy gold:
Offer a trade to another civilization (a technology or resource they do not have) for an exorbitant amount of money. For example, coal for 2 followed by as many zeros as can fit. Do this once per turn.
Information in this section was contributed by Peaceknuckle.

Hint: Trade for everything:
If you are at war with another nation, to trade for everything they have, type in as many 9s as you can in the money received per turn. They will willingly trade anything they have for one of your territory maps (or anything else.)
Information in this section was contributed by Adam Lee.

Hint: Prevent city capture:
Get a worker to fortify himself in a city or town that you do not want to be captured in a war. They, have it be fortified, and it has to be a worker. When an enemy attacks the city, it will do so, but will hurt itself. Note: The enemy will probably retreat in battle. Note: If you have a unit that can attack others instead of a worker, the opponent will die, but your person will usually be only slightly damaged. Note: Catapults, ships, airplane, etc. that attack with a bombardment will not be affected.
Information in this section was contributed by FLD58ANC.

Hint: Trap opponents in cities:
strong people that can fight to fortify around an enemy city. Enemies cannot get in or out without attacking you.
Information in this section was contributed by FLD58ANC.

Hint: Blocking your borders:
Fortify people that can fight around your borders and no one can get inside them.
Information in this section was contributed by FLD58ANC.

Hint: Get leaders faster:
Find a barbarian camp, then fortify your unit (not artillery, catapult, or anything that rolls on wheels) near the camp. The barbarians will come to your unit and start defending their camp. If this works, your unit will be a leader faster.
Information in this section was contributed by GameFreak0208.

Hint: Upgrading your city past 6:
You do not need the Adaquit upgrade; you just need your settler to set up a city on a river and your population will grow past 6 without the upgrade.
Information in this section was contributed by GameFreak0208.

Hint: Finding resources beter:
Start a new game without another rival. Set the world size to the smallest value, then set the button up on no barbarians or sedentary. You can now explore the world without interruption to find resources easier.
Information in this section was contributed by GameFreak0208.

Hint: Getting small wonders and great wonders:
Set the game to no rivals and any world size. You can now build small and great wonders in your city without the enemy stealing them.
Information in this section was contributed by GameFreak0208.

Hint: Faster units:
Find out how to learn steam power. You need the resource iron in your city and all your other cities. You can now build railroad tracks which do not take any movement points.
Information in this section was contributed by GameFreak0208.

Hint: Free units and city improvements:
While in the map editor, after you finish placing everything desired, activate the customize rules menu in the scenario bar. Then in the rules bar, select "Edit Rules". Then, click on the "Government tab" and click "All Units Free" at the bottom left of the window. This makes it so that all units cost nothing to maintain. Then, unselect the "Requires Maintenance" box and all city improvements are now free to maintain. You can now spend money on other things, and it works on all the governments. It turns any government into the fundamentalism government of Civilization 2.
Information in this section was contributed by Joshua Roe.

Hint: Little corruption and war weariness:
Note: This only works with the map editor. From the "Government" tab of the edit rules window, you can reduce "Corruption" to minimal and set "War Weariness" to none for the democracy government.
Information in this section was contributed by Joshua Roe.

Hint: Make any government immune to propaganda and other spy techniques:
Note: This only works with the map editor. From the "Government" tab of the edit rules window, change the "Immune to" box to whatever desired. Note: This will only prevent one type of spy move, not all.
Information in this section was contributed by Joshua Roe.

Hint: Make changes to any civilization:
Go to the scenario menu and click "Customize Rules". Then, go to the rules bar and choose "Edit Rules". Click the "Civilization" tab and make any changes desired. You can make it so that your enemies may not build wonders or build naval units, and you can also change the names of cities and leaders.
Information in this section was contributed by Joshua Roe.

Hint: Best government:
First, learn all of the governments such as Monarchy, Republic, Despotism (available from the start), Communism, and Democracy. The best government to get first is Despotism, then Democracy. Your troops will be more efficient, faster, and work harder.
Information in this section was contributed by GameFreak0208.