The Art of Conquest expansion pack for Empire Earth includes three new single-player campaigns set in ancient Rome, the Pacific theater of World War II, and Asia in the 22nd century. In addition, each of the 21 predesigned civilizations in the game gains a unique power, building, or unit. Examples include: the Kingdom of Italy's metallurgy power, which allows it to pay building costs with gold or iron interchangeably; Great Britain's S.A.S. unit which can plant demolitions and swim across water; and the United States' market building which allows that civilization to trade abundant resources for scarce ones.