Washington Monument facts and history: why the colour changes a third of the way up, the 36-year pause, the pope's stone, the aluminium tip and the numbers

Architecture · 4 September 2026

The Washington Monument on the National Mall in Washington, D.C. is a marble obelisk 555 feet 5 inches (169 m) high, the tallest stone structure and the tallest obelisk in the world, begun in 1848, abandoned as a 152-foot stump from 1854 to 1879 for lack of money and because of the Civil War, finished by the Army Corps of Engineers in 1884, and opened to the public in 1888; it was the tallest structure in the world from 1884 until the Eiffel Tower in 1889 and is still the tallest building in Washington by law. The line where its colour changes, a third of the way up, marks the 25-year pause and the marble from a different quarry; its tip is a 9-inch pyramid of aluminium, in 1884 a rare metal worth as much as silver; and inside its walls are 193 stones given by states, cities, countries, lodges and the Pope, whose stone was stolen and thrown in the Potomac by the anti-Catholic Know-Nothings in 1854. Below: the design and its long birth, the pause, the finish, the colour line and the tip, the stones inside, the records, the earthquake of 2011 and the myths, with the memorial at the other end of the reflecting pool in how the Lincoln Memorial was built.

The design and its long birth

Congress voted a monument to Washington in 1783, while he was alive, and did nothing; L'Enfant's plan of 1791 reserved the spot at the crossing of the Capitol's and the White House's axes for an equestrian statue; in 1833 private citizens formed the Washington National Monument Society, and in 1836 held a competition that Robert Mills, the architect of the Treasury and the Patent Office, won with an obelisk 600 feet high rising from a circular Greek colonnade 250 feet across with a statue of Washington in a chariot on top, at a cost of a million dollars; the society had 87,000 and built the obelisk first, without the colonnade, which was never built. The cornerstone, 24,500 pounds, was laid on 4 July 1848 with the trowel Washington had used at the Capitol in 1793, before 20,000 people including Lincoln, then a congressman, and the shaft rose in Maryland marble from the Texas quarry near Baltimore, 15 feet thick at the base, on a foundation 24 feet deep that proved too shallow. Washington Monument.

The Pope's stone and the stump, 1854–1879

To raise money the society asked states, cities, societies and foreign governments for carved memorial stones to be set in the inner walls, and in 1852 Pope Pius IX sent a block of marble from the Temple of Concord in Rome; on the night of 6 March 1854 members of the American Party, the anti-Catholic and anti-immigrant "Know-Nothings", broke into the works, stole the stone, and are believed to have smashed it and thrown it in the Potomac. In 1855 the Know-Nothings rigged the society's election, took it over, ran it into the ground, added 26 feet of bad masonry that was later removed, and lost the public's money and Congress's; the society got itself back in 1858 with no funds, and in 1861 the Civil War stopped everything. For 25 years a stump of 152 feet stood on the Mall, with cattle grazing around it and the Army using the grounds as a slaughterhouse and drill ground during the war, and Mark Twain called it "a factory chimney with the top broken off"; it appears in the background of every photograph of the Mall of the 1860s and 70s. In 1876, for the centennial, Congress took over the monument, voted 200,000 dollars, and gave the job to the Army Corps of Engineers under Lieutenant Colonel Thomas Lincoln Casey.

Casey finishes it, 1879–1884

• The foundation. Casey found the shaft had tilted and the foundation was too small for the weight; in 1879–80 he underpinned it, digging out beneath the old footing and pouring a new concrete foundation two and a half times the area, 37 feet deep, while the 32,000-ton stump stood on top, without moving it, the most dangerous part of the work.
• The design. Mills's colonnade was dropped and the obelisk was reproportioned to the Egyptian rule, the height ten times the base width, 555 feet on a 55-foot base, with a pyramidion at the top of 55 feet, on the advice of George Perkins Marsh, the American minister to Italy, who measured the obelisks of Rome.
• The marble. The Texas quarry had closed; stone from Sheffield, Massachusetts, was tried for four courses and rejected as too dark, and the rest came from the Cockeysville quarry in Maryland, of the same white marble as the first but a different bed, which weathered differently; the change is visible at 152 feet, with the Massachusetts courses as a second faint line just above it.
• Building. A steam hoist inside the shaft lifted the blocks, up to 4 tons, and the walls thinned from 15 feet at the base to 18 inches at the top; the shaft rose 200 feet in the summer of 1884, and the capstone, 3,300 pounds, was set on 6 December 1884 by Casey himself in a gale, with the aluminium apex on top; the dedication was on 21 February 1885, in the cold, and the interior with its iron stair and steam elevator opened on 9 October 1888.
• Cost. 1,187,710 dollars in all, of which the society had spent 300,000 for the stump and Congress about 890,000 to finish it.

The aluminium tip

The apex of the monument is a pyramid of cast aluminium 8.9 inches high and 5.6 inches at the base, weighing 100 ounces, made by William Frishmuth of Philadelphia, the only man in America then producing the metal, as a lightning conductor that would not corrode; in 1884 aluminium cost 1 dollar an ounce, about the price of silver, and Frishmuth's pyramid was the largest piece of aluminium ever cast, exhibited at Tiffany's in New York before it was set, where visitors were invited to step over it and say they had stepped over the top of the Washington Monument. Two years later Hall's electrolytic process made aluminium cheap. The tip is engraved on four faces with the names of the commission, the engineers, the dates and "Laus Deo", Praise be to God; lightning has struck and pitted it, and copper rods around it took over the job in 1885 after the first strike showed the aluminium was not enough.

The stones inside

Set into the inner walls of the shaft along the stair are 193 memorial stones, given from 1849 to 1982: from every state, the territories, cities and towns, fire companies, Masonic and Odd Fellows lodges, the Sons of Temperance, the Cherokee Nation, the Ryukyu Kingdom of Okinawa, Greece with a marble from the Parthenon, Turkey, Brazil, Wales, Switzerland, Bremen, the Templars of Honor, the Sunday schools of New York, and Alaska in jade in 1982; the Pope's replacement stone was given in 1982 by Catholic groups; and one, from the state of Utah, was set as "Deseret" by the Mormons in 1853. The stones are seen on the "walk-down" tours of the 897 steps, which the Park Service gives rarely, the stair having been closed to the public in 1976 after vandalism and the elevator's windows showing a few stones on the descent.

The numbers

• Height. 555 feet 5 and 1/8 inches (169.3 m) to the tip; 554 feet 7 inches by the 2013–14 survey to a different base; the tallest stone structure, tallest obelisk and tallest building in Washington, and the tallest structure in the world from 1884 to 1889.
• Base. 55 feet 1.5 inches square; walls 15 feet thick at the base and 18 inches at the top.
• Weight. About 81,000 tons; 36,491 blocks of marble, granite and gneiss, the outer marble 7 inches thick over a granite and rubble core.
• Stairs and elevator. 897 steps and 50 landings; the elevator of 1888 took 10 to 12 minutes, the present one 70 seconds; the observation room at 500 feet has eight windows.
• Time. 1848–54 for the stump, 1879–84 for the rest, 36 years in all; opened 1888.
• Sway. About 0.125 inch in a 30-mile-an-hour wind; the monument sinks about 2 inches a century.
• Visitors. About 600,000 a year, by free timed ticket, 20 at a time in the elevator; closed 2011–14 for the earthquake, 2016–19 for the elevator, and 2020–21.

The earthquake and since

On 23 August 2011 a magnitude 5.8 earthquake in Virginia, felt across the East Coast, cracked the pyramidion, loosened stones at the top, and sent chips of marble and mortar falling inside; engineers roped down the outside to inspect it in the weeks after, and the monument was closed for 32 months while 150 cracks were repaired and the top re-pointed, at a cost of 15 million dollars half paid by the philanthropist David Rubenstein, and reopened in May 2014. The elevator failed repeatedly and was rebuilt in 2016–19 with a new security screening building at the base, and the monument reopened again in September 2019. The 50 American flags around the base, the reflecting pool to the west of 1923, the Lincoln Memorial at its far end and the Jefferson Memorial across the Tidal Basin are its setting; the Mall's cherry trees bloom around it in April, and on 4 July the fireworks are launched from the grounds.

Versions and theories

• The colour changes because of the Civil War. Because of the 25-year pause that the war was part of, and the quarry change; the stone was from the same Maryland marble belt but a different bed, and it has weathered to a different tone. The line is at 152 feet.
• The monument is sinking or leaning. It settled 2 inches in its first century and is stable; Casey's underpinning of 1880 holds it. The 2011 quake did not move it.
• The tip is gold. Aluminium, chosen for lightning and because it does not tarnish; it was worth as much as silver in 1884 and is worth a few dollars now.
• The Pope's stone is in the Potomac. Probably; the Know-Nothings' story was that they dropped it in the river, and it has never been found, though a fragment was claimed in 1892. The replacement of 1982 is inside.
• Nothing in Washington may be taller. The Height of Buildings Act of 1910 limits buildings by street width, to about 130 feet, which keeps the monument the tallest; the Basilica of the National Shrine's tower is 329 feet, the Cathedral's 301, on higher ground.
• The monument is a Masonic symbol. Washington was a Mason and Masons laid the cornerstone, as they had at the Capitol; the obelisk is Egyptian, by way of Rome and Mills, and the 555-foot height and 55-foot base are the Egyptian proportion, not a code.

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