The list of units
The first wheeled unit you can build, chariots move fast and withdraw from combat if losing the battle (unless fighting another fast unit).
Chariots may not enter jungles or mountains unless on a road. A city must have horses in its Strategic Resource box to build chariots.
The chariot was the first true fighting vehicle. Ancient armies used it to transport archers and other troops to the battlefield, where they would disembark and fight. The Assyrians, whose archers and spearmen fought from inside the chariot itself, turned the vehicle into a fearsome offensive weapon. Few enemies were able to withstand an onslaught of Assyrian chariots. This devastating form of attack was soon adopted by many of the Assyrian's enemies, who used the chariot against them with good effect.