George Washington was much more than just the first President of the United States, and his monument in Washington, DC is much more than just a building.
Before George Washington served as President from 1789 to 1797, he lead the Continental Army to defeat the British and secure independence for the United States. He also lead the Continental Convention to create the United States’ most valuble governmental document, the Constitution. One of his first duties as President was to survey the Potomac River area to find a suitable place for the nation’s new capital. It is only fitting that the Washington Monument be the most prominent structure in this city.
The Washington Monument, the tallest building in Washington, DC, also houses the nation’s most unique rock collection. The stones on the outside help preserve the history of the monument’s construction. Meanwhile, the stones on the inside make a visit to the Washington Monument like a geology field trip around the world, including all 50 states and several national parks. Through geology, the whole country truly comes together to honor the first President of the United States.
The Washington National Monument Society formed in 1833 to honor George Washington with a proper monument in the capital city. What was first envisioned as an equestrian statue grew into a larger and grander monument as the society requested different designs.
Robert Mills designed an impressive and ornate structure that drew on an ancient Egyptian design –an obeliesk-- as its centerpiece. A traditional obelisk should measure 10 times higher than it is wide at the base, and be carved from a single block of stone.
As designed, the Washington Monument obelisk would be 600 feet tall –taller than any other builing in the world-- and made from over 36,000 individual blocks. There was also to be a decorative collenade surrounding the base with space for several statues.
Construction began on the Washington Monument in 1848, but unfortunately stopped in 1853 because there was no money to continue. The monument was only 150 feet tall at that time. In 1878 Congress appropriated funds to complete the Washington Monument, without the decorative colledade. Thomas Casey, an engineer with the Army Corps of Engineers, made measurments and changes to the monument’s design. Because the base was only slightly wider than 55 and a half feet, not 60 feet (x 10 = 600ft), the monument could only go up slightly more than 555 feet. When it was finished in 1884, it was the world’s tallest building. Today, at 555 feet, 5 1/8 inches, the Washington Monument is no longer the world’s tallest building, but it does hold the record as the world’s tallest free standing stone building. The stone supports itself without help from steel beams or anything else.
How does the geology of the building materials help preserve the story of construction?
Since the Washington Monument has no structural support other than the stone itself, the building materials needed to be not only beautiful, but strong as well. White marble on the outside is backed with gneiss and granite on the inside to make 15 foot thick walls at the base which taper to 18 inches at the top. Almost all of the white marble on the outside was quarried near Baltimore, Maryland from two quarries just a mile apart. A few layers near the color change show white marble from Massachusettes. Metamophic Piedmont rock (gneiss) from Little Falls, Maryland fills in the thick walls below 150 feet while granite from Maine was used above 150 feet. A pyramid shaped alluminum capstone sits at the monument’s tip. In the lates 1800s, alluminum was more precious than silver or gold.
The Washington Monument stands not only because of the structural support of its construction stones, but also because of the symbolic support of its commemorative stones. During –and even after—the construction of the monument, 193 commemorative stones were donated by individuals, groups, cities, foreign countries, and all 50 states. These stones are carved works of art which also give us a way to see 193 different kinds of rock in a single building! Take a virtural tour of the staircase inside the Washington Monument from both a geologist and a historian to conclude your GeoStory Tour of the National Mall.
Visit the Washington Monument online or view the 193 commemorative stones.
Stop 1: The Geology of the Washington D.C. Area
Stop 2: The History of Washington D.C.
Stop 3: Finding D.C.’s Foundation
Stop 4: A Watery Past
Stop 5: GeoStory of the Lincoln Memorial
Stop 6: Remembering War
Stop 7: Stories in Stone at the Franklin Delano Roosevelt Memorial
Stop 8: Thomas Jefferson Memorial - A Place of Controversy
Stop 9: Washington Monument - The Nation’s Most Unique Rock Collection
Stop 10: Who Cares for the National Mall
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