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The Dalles Lock and Dam was one of the largest, most complete, and complex multipurpose projects of its kind in the United States at the time of its construction. It provided an example for future projects benefitting navigation, recreation, water for irrigation and hydropower, fish migration, and flood mitigation. The unusual "L" configuration of the project enabled reduced construction dewatering and created a permanent shallow stilling basin that aids fish passage.

The Rogue River Bridge was the most advanced concrete bridge in America when it was built. Distinguished bridge engineer Conde McCullough employed the techniques of Frenchman Eugene Freyssinet to create thin, graceful concrete arches for this seven-span structure.

Pre-compression of the concrete arch was achieved and, as a result of its success, pre-stressing became one of the hallmarks of American bridge building techniques.

Better known as the "Spruce Goose," the Howard Hughes Flying Boat was designed and built by Hughes Aircraft Co., to be the largest wood-constructed and the largest wingspan airplane ever built. As Hughes perfected his craft, he added significantly to what is known in areas of large-lift capability and power-boost systems. Originally designated the HK-1 in 1942, it was designed to meet wartime troop and material transportation needs (flying just high enough to evade submarine attacks).

The use of heat pumps for the heating and cooling of the Commonwealth Building, initiated in 1948, was a pioneering achievement in the western hemisphere. The theoretical conception of the heat pump was described in a neglected book, published in 1824 and written by a young French army officer, Sadi Carnot. Its practical application on a large scale is attributable to designers J. Donald Kroeker and Ray C. Chewning, building engineer Charles E. Graham, and architect Pietro Belluschi.

A project that combined great engineering ambition and burgeoning civic pride, the Columbia River Highway was built at the dawn of the automobile age out of a desire to bring greater attention to the growing population and natural beauty of the Pacific Northwest. By the time of its completion in the 1920s, the 73.8-mile highway had become a textbook example of modern highway construction and an important commercial and recreational link between Oregon's coastal Willamette Valley and the inland areas of eastern Oregon and Washington. 

The Bonneville Dam, Columbia River Power and Navigation System consists of 55 major projects on Oregon's Columbia River and is said to be the largest hydroelectric system in the world.

The Columbia River forms part of the border between Washington and Oregon and flows inland through the only waterway that crosses the Cascade Mountains. To harness the energy of the ninth longest river in North America, engineers developed unique design and construction approaches to overcome problems caused by depth of water, current velocity, and an irregularly-shaped river bottom.