They block the force of a river, produce enough electricity to power cities, move water over hundreds of miles and irrigate fertile valleys. Dams prevent floods and produce "green" energy. We'll visit a hydroelectric dam, the most technologically advanced type of dam, and a dam in Brazil that is five times the size of the Hoover Dam. At the Utah State University Water Research Laboratory Hydraulics Lab in Logan, Utah, we watch a model of a dam crumble beneath tons of water and discuss how future dam failures can be averted. We will learn how dams adversely affect river systems and as a result, there are many proponents of dam removal.