 After the First World War, tourism boomed again, as automobiles made getting to the falls much easier.The story of Niagara Falls in the 20th century is largely that of efforts to harness the energy of the falls for hydroelectric power, and to control the development on both sides that threaten the area's natural beauty.In 1941, the Niagara Falls Bridge Commission completed the third current crossing in the immediate area of Niagara Falls with the Rainbow Bridge, carrying both pedestrian and vehicular traffic between the two countries and Canadian and U.S. customs for each country.