How tall is the Washington Monument, including its pyramidion?

The Washington Monument is 555 feet tall, including its pyramidion.

The obelisk on the National Mall in Washington, D.C., commemorates George Washington, the first president of the United States. Construction began in 1848, stopped from 1854 to 1877, and resumed after the Civil War. The monument was completed in 1884 and opened to the public in 1888.

Its design is a hollow Egyptian-style obelisk with a 500-foot stone shaft topped by a 55-foot aluminum pyramidion. Construction interruptions produced a visible change in the color of the marble partway up the monument because different quarries supplied stone for the two building phases.

The Washington Monument was the world’s tallest structure from 1884 until 1889, when the Eiffel Tower surpassed it. Its height is sometimes reported as approximately 554 feet in modern geodetic measurements, but the standard architectural figure and familiar trivia answer is 555 feet.