Gateway Arch – St. Louis, USA

Among the more peculiar and modern-looking monuments in the world is the famous Gateway Arch in St. Louis, Missouri.  It is actually part of the larger Jefferson National Expansion Memorial, designated as a celebration of the starting point for the Lewis and Clark Expedition and the Louisiana Purchase. 

History

The Memorial site was designated in 1935 and sprawls over 90 acres along the Mississippi River on the site of the original city of St. Louis.  The Gateway Arch was proposed in 1947 after civic leaders selected an architect from a national competition for the main portion of the memorial space. 

The winner was a young American architect with Finnish heritage: Eero Saarinen.  His plans for a 590-foot catenary arch won by a large majority.  It was not built right away, however.  Over the next 15 years his plans would be revised and expanded with an additional 40 feet of height and width.

Construction began in February of 1963, and after $15 million dollars of expenditures it was completed in 1965.  It was inducted as a national monument in 1966.

Description

The arch glistens on the St. Louis landscape and stands at 630 feet in both height and width.  It is currently the tallest structure in the city.  The shape of the arch along its length is an equilateral triangle.  It begins as a triangle with 54-foot sides to a triangle with 15-foot sides at the peak.  The overall shape o the arch is a catenary, which is the natural shape of a rope or flexible chain that hangs under gravity.  The catenary is the ideal shape for a static load under gravity, and hence the arch is perfectly self-supporting.