Gateway Arch in the context of Gateway Arch National Park

An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but structural load-bearing arches became popular only after their adoption by the Ancient Romans in the 4th century BC.

Arch-like structures can be horizontal, like an arch dam that withstands a horizontal hydrostatic pressure load. Arches are usually used as supports for many types of vaults, with the barrel vault in particular being a continuous arch. Extensive use of arches and vaults characterizes an arcuated construction, as opposed to the trabeated system, where, like in the architectures of ancient Greece, China, and Japan (as well as the modern steel-framed technique), posts and beams dominate.

Eero Saarinen (/ˈeɪroʊ ˈsɑːrɪnən, ˈɛəroʊ -/, Finnish: [ˈeːro ˈsɑːrinen]; August 20, 1910 – September 1, 1961) was a Finnish-American architect and industrial designer. Saarinen's work includes the General Motors Technical Center; the Dulles International Airport Main Terminal; the TWA Flight Center at John F. Kennedy International Airport; the Vivian Beaumont Theater at Lincoln Center; the Gateway Arch; and the IBM Thomas J. Watson Research Center. During his career, Saarinen was elected a Fellow of the American Institute of Architects and served on the National Institute of Arts and Letters.

Born in Hvitträsk, Finland, he was the son of Finnish architect Eliel Saarinen, and immigrated to the United States as a teenager. Saarinen grew up in Bloomfield Hills, Michigan, studying at the Cranbrook Academy of Art, where his father taught. Saarinen became a naturalized citizen of the United States in 1940, a year after marrying the sculptor Lilian Swann, with whom he had two children. After divorcing Swann in 1954, Saarinen married Aline Bernstein Louchheim. In 1961, Saarinen died while undergoing an operation for a brain tumor.

High modernism (also known as high modernity) is a form of modernity, characterized by an unfaltering confidence in science and technology as means to reorder the social and natural world. The high modernist movement was particularly prevalent during the Cold War, especially in the late 1950s and 1960s.

The Basilica of Saint Louis, King of France (French: Cathédrale Saint-Louis-Roi-de-France de Saint-Louis), formerly the Cathedral of Saint Louis, and colloquially the Old Cathedral, is a Catholic church in St. Louis, Missouri. It was the first cathedral west of the Mississippi River and until 1844 the only parish church in St. Louis. It is one of two Catholic basilicas in St. Louis (with the current cathedral) and both are named for King Louis IX of France (the namesake of the city).

The current structure (built 1831–1834) is located near the historic riverfront of St. Louis. It is surrounded by Gateway Arch National Park. However, the church is not part of the park. Because of the historical significance of the church, it was left intact while all neighboring buildings were demolished to make way for the Gateway Arch and related park. Rev. Nicholas Smith serves as Rector.

A weighted catenary (also flattened catenary, was defined by William Rankine as transformed catenary and thus sometimes called Rankine curve) is a catenary curve, but of a special form: while a catenary is the curve formed by a chain under its own weight, a weighted catenary is the curve formed if the chain's weight is not consistent along its length. Formally, a "regular" catenary has the equation

for a given value of a. A weighted catenary has the equation

The tallest structures in the U.S. state of Missouri include a 2,000-foot (610 m) broadcasting tower, an 800-foot (240 m) chimney, a 630-foot (190 m) monument, and a 624-foot (190 m) office building.