The Washington Monument is an obelisk on the National Mall in Washington, D.C., built to commemorate George Washington, once commander-in-chief of the Continental Army (1775–1784), in the American Revolutionary War and the first President of the United States (1789–1797). Located almost due east of the Reflecting Pool and the Lincoln Memorial, the monument, made of marble, granite, and bluestone gneiss, is both the world's tallest predominantly stone structure and the world's tallest obelisk, standing 554 feet 7 11⁄32 inches (169.046 m) tall according to the U.S. National Geodetic Survey (measured 2013–14) or 555 feet 5 1⁄8 inches (169.294 m) tall according to the National Park Service (measured 1884). It is the tallest monumental column in the world if all are measured above their pedestrian entrances. Overtaking the Cologne Cathedral, it was the tallest structure in the world between 1884 and 1889, after which it was overtaken by the Eiffel Tower in Paris.
Construction of the monument began in 1848 and was halted for a period of 23 years, from 1854 to 1877 due to a lack of funds, a struggle for control over the Washington National Monument Society, and the American Civil War. Although the stone structure was completed in 1884, internal ironwork, the knoll, and installation of memorial stones were not completed until 1888. A difference in shading of the marble, visible approximately 150 feet (46 m) or 27% up, shows where construction was halted and later resumed with marble from a different source. The original design was by Robert Mills (1781–1855) of South Carolina, but he did not include his proposed colonnade due to a lack of funds, proceeding only with a bare obelisk. The cornerstone was laid on July 4, 1848; the first stone was laid atop the unfinished stump on August 7, 1880; the capstone was set on December 6, 1884; the completed monument was dedicated on February 21, 1885; and officially opened October 9, 1888.