USA

This wind tunnel complex was developed by the National Advisory Committee for Aeronautics (NASA's predecessor) to serve the emerging need for supersonic research and development following World War II. The three-testing-section configuration covers Mach number .03-3.5 and utilizes a single common drive and two compressors.

Established in 1939 by the National Advisory Committee for Aeronautics (NACA), and named after NACA’s first chairman, Joseph S. Ames, the center has been at the forefront of American, and worldwide, aeronautics research.

The Arecibo Observatory has the largest radio telescope ever constructed. Maintaining the greatest electromagnetic wave gathering capacity of any telescope, it has been an essential tool in modern astronomy, ionosphere and planetary studies. Several feats of mechanical engineering went into the construction of this observatory, most notable of which is a drive system which allows all active parts of the antenna to be kept focused with millimeter precision regardless of environmental factors—such as thermal expansion.

The Mullan Road was designed to facilitate the movement of troops and supplies across the Rocky Mountains between the Missouri River basin in the Great Plains and the Columbia River Basin at the Columbia Plateau during times of Indian hostilities. But because peace was reached with the Northwest Indians early on, the road was used only once (in 1860) for military means. Instead, it became a popular thoroughfare for emigrants and fortune-seekers during the Montana and Idaho gold rushes of the 1860s. 

Designed, patented, and built by Thomas W.H. Moseley, this arched 96-foot span bridge preceded by years the standard use of wrought iron for bridges. For the first time in the United States, Moseley incorporated the use of riveted wrought-iron plates for the triangular-shaped top chord.

This reaction or "Scotch" turbine had as its antecedent the steam reaction wheel invented in Greek Alexandra by Hero around 100 B.C.. It found widespread hydraulic application in the United States from the beginning of the nineteenth century to mid-century when French-inspired hydraulic turbine design pushed reaction wheels into obsolence.

Just 20 years after settling the uninhabited Salt Lake valley, Brigham Young and his Mormon followers completed one of the nation's most impressive public structures. The 9,000-seat Mormon Tabernacle boasts a clear span roof measuring 150 feet by 250 feet, its timber trusses joined with wooden pegs and lashed with green rawhide, which shrank and tightened as it dried.

The Memphis Bridge (now called the Frisco Bridge) comprises three spans across the Mississippi River. With a main span measuring over 790 feet, it was one of the longest railroad bridges in the world upon completion. The renowned George Morison, after whom the bridge is unofficially named, served as Chief Engineer.

The glider was the first heavier-than-air human-carrying aircraft to achieve controlled piloted flight. On his first successful flight, August 28, 1883, John Montgomery soared at about 600 feet. The Montgomery glider's success demonstrated aerodynamic principles and designs fundamental to the modern aircraft.