Pierre Charles L'Enfant (the architect who designed Washington, D.C.) planned in 1783 to have a prominent statue honoring George Washington near the White House and Capitol. But exactly how to honor the first President of the USA was not an easy decision, and in 1833, the Washington National Monument Society was formed with the purpose of deciding upon an appropriate memorial. This group had a design competition, and in 1836, the architect Robert Mills' obelisk design won the contest.

Work on the stone monument to George Washington did not begin until July 4, 1848 (because of a lack of funds). Work on the monument was stopped in 1854 (when the monument was only 152 feet tall), after donations dropped off. The project was almost abandoned, but work finally began again in 1876 (you can see the slight difference in color of the marble on the bottom third and the upper two-thirds of the monument). Also, the Army Corps of Engineers, who started working on the monument after the Civil War, determined that the foundation was not sufficient for the 600-foot-tall obelisk that was originally planned, so a 550-foot-monument was built.

The exterior of the Washington Monument was completed on December 6, 1884; it was opened to the public on October 9, 1888 (after the interior was completed). The giant obelisk contains 36,491 blocks and weighs 90,854 tons.

Inside the Washington Monument are an elevator and a 897-step stairway. There is an observation deck at 500 feet. At the top of the monument there is a nine-inch tall aluminum pyramid (when the monument was built, aluminum was newly-discovered, scarce, and very expensive). Lightning rods at the top protect the monument from lightning strikes.