The Catapult is replaced by the following unique units:
The Catapult is used to take down city defense and damage multiple units on the same tile (though it doesn't do a good job damaging multiple units).
The catapult was one of the earliest forms of artillery, with records indicating that they were in use by the Greeks as far back as 400 BC. It was a large mechanical arm that propelled heavy stones and other missiles from a great distance, battering down walls and inflicting damage on buildings and defenders. Catapults could easily launch projectiles 500 to 1000 feet with a surprising amount of force behind them. Though cumbersome and nearly useless on the battlefield, the catapult was an effective weapon for siege operations.