2002

Designed by David B. Steinman, of Robinson & Steinman, New York City, the Waldo-Hancock suspension Bridge is a significant example of Steinman's work. David Steinman is considered among the most important suspension bridge designers of the 20th century. He earned an engineering degree from Columbia University in 1909 and went on to apprentice with Gustav Lindenthal, then at work on New York's Hell Gate Bridge. In the 1920's, Steinman emerged as an outstanding and innovative suspension bridge designer.

Built between 1819 and 1826, the Menai Bridge was the major structure on Britain's strategically important Holyhead Road connecting London with Holyhead and by sea to Ireland. Designed by Thomas Telford, the bridge's main span was 579 feet from tower to tower, the longest that had ever been attempted at this time. He used four sets wrought-iron eyebars to suspend the deck. These were made by William Hazledine at his Upton forge near Shrewsbury. Each bar was carefully tested in his Coleham shops before being pinned together and lifted into place.

The Portland Head Light was the first lighthouse to be constructed in Maine and the first one completed and put into service by the Federal government under the Lighthouse Act of 1789, which moved to place all lighthouses under federal control. While work had begun on the lighthouse in 1787 by the State of Massachusetts which, at that time, had jurisdiction over Maine, it was completed by the Federal government. When this lighthouse was being built, Portland was the sixth largest port in the country, the closest port to Europe and had significant trade with the Caribbean.

The Pilatusbahn—the steepest rack railway in the world—has operated successfully since its opening in 1889 over a route of 4.62 kilometers (2.87 miles) between Alpnachstad on Lake Lucerne and Pilatus Kulm, rising 6,791 feet (2,070 meters) above sea level. This results in a gradient of 48%, or a rise of nearly one meter in two meters of run on the steepest sections of the line, which amounts to about a quarter of its length.

Designed by Claude A. P. Turner, a pioneer of reinforced concrete construction, the Marshall Building was constructed originally in 1906 as a five-story building. In 1911 the sixth floor of the building was added as per Turner's original design. This building is the oldest extant example of Turner's "mushroom" flat-slab system which transformed the design and construction of reinforced-concrete floors worldwide.

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 Dorton Arena was the first use of a cable-supported roof system in the world. Commissioned in 1949 by North Carolina State Fair manager J.S. Dorton, the new building was intended to be a livestock judging pavilion. Architect Matthew Nowicki (1910 - 1950) proposed a structure that included a pair of intersecting parabolic arches supported by slender columns around its perimeter with a network of wire cables that supported the saddle-shaped roof.

Built by Robert Stephenson to carry the Chester and Holyhead Railway across the River Conwy, this bridge was erected between 1846 and 1848. It consists of a single span 400 feet long, formed by two parallel rectangular wrought iron tubes, each weighing 1300 tons. Masonry towers were built on the abutments and topped with battlements and turrets to harmonize with the nearby Conwy Castle. The Conwy Tubular Bridge was the first railway bridge in which trains ran through the main girders. It represents a pioneering use of wrought iron for bridges.

When a new road bridge was constructed alongside it, plans were made to demolish the Conwy Suspension Bridge. There was a national outcry and, since 1958, the bridge has been in the care of the National Trust and closed to vehicular traffic.