USA

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.

As a practical conveyance during the horse-and-buggy era, the Monongahela Incline was one of seventeen built and operated in Pittsburgh in the last century. Of the seventeen, the Monongahela and the Duquesne are the only two remaining operating units. While the Mt. Washington Incline was known as a coal-carrying incline plane in 1854, the Monongahela Incline is probably the earliest passenger-carrying incline in the United States and has been in continuous successful service since its construction.

Known as "the highest and lowest holing in history," the tunnel bored through the Rockies at an elevation of 9,200 feet, 2,800 feet below the surface. Eight hundred men worked around the clock for 3 1/2 years, moving 3 billion pounds of rock. 

When Ford Motor Company introduced its new Model T on October 1, 1908, even an inveterate optimist like Henry Ford (1863-1947) could not predict the vast changes that his rather homely new vehicle would produce. What flowed from this series of bold innovations was more than an endless stream of Model Ts — it was the very foundation of the twentieth century itself. The assembly line became the century's characteristic production mode, eventually applied to everything from phonographs to hamburgers.

Minot's Ledge is a wave-swept rock formation in a rocky area of ocean about a mile off the Cohasset shore near Boston. Numerous serious shipwrecks prompted the government to erect a beacon there, and construction began in the summer of 1847.  

The light, constructed on tall iron legs, was put into operation on January 1, 1850. Designers believed that the water would flow freely through the legs, leaving the lighthouse intact. But a terrible winter storm toppled it in 1851, killing the two assistant keepers.  

This was America's first large-scale activated sludge plant. The successful operation of Milwaukee's sewage treatment plant led the way for many other American municipalities to adopt its methods of efficient environmental recycling.

Prior to 1925, sewage and industrial waste from the City of Milwaukee and its suburbs (then population 500,000) was discharged to the Milwaukee, Menomonee, and Kinnickinnic rivers, which converge in Milwaukee and flow together through a single outlet into Lake Michigan.