Washington monument

The Washington Monument is an obelisk near the west end of the National Mall in Washington, D.C., built to commemorate the first U.S. president, General George Washington. The monument, made of marble, granite, and bluestone gneiss, is both the world's tallest stone structure and the world's tallest obelisk, standing 555 feet 5 /₈ inches (169.294 m). There are taller monumental columns, but they are neither all stone nor true obelisks. It is also the tallest structure in Washington D.C.. It was designed by Robert Mills, an architect of the 1840s. The actual construction of the monument began in 1848 but was not completed until 1884, almost 30 years after the architect's death. This hiatus in construction happened because of co-option by the Know Nothing party, a lack of funds, and the intervention of the American Civil War. A difference in shading of the marble, visible approximately 150 feet (46 m) or 27% up, shows where construction was halted for a number of years. The cornerstone was laid on July 4, 1848; the capstone was set on December 6, 1884, and the completed monument was dedicated on February 21, 1885. It officially opened October 9, 1888. Upon completion, it became the world's tallest structure, a title previously held by the Cologne Cathedral. The monument held this designation until 1889, when the Eiffel Tower was completed in Paris, France. The monument stands due east of the Reflecting Pool and the Lincoln Memorial.

The Washington Monument was originally intended to be located at the point at which a line running directly south from the center of the White House crossed a line running directly west from the center of the Capitol. Pierre (Peter) Charles L'Enfant's 1791 "Plan of the city intended for the permanent seat of t(he) government of the United States ..." designated this point as the location of the equestrian statue of George Washington that the Continental Congress had voted for in 1783. However, the ground at the intended location proved to be too unstable to support a structure as heavy as the planned obelisk. The Jefferson Pier, a small monolith 390 feet (119 m) WNW of the Monument, now stands at the intended site of the structure.