Washington Monument Timeline

In a ceremony attended by President James K. Polk and an estimated 20,000 people, Freemasons laid the monument's 24,500-pound cornerstone, with a speech by Speaker Robert C. Winthrop.

A block of marble donated by Pope Pius IX was stolen and destroyed by members of the anti-Catholic Know-Nothing Party, an act that contributed to a collapse of public donations and halted construction.

Image source: The Pope's Exorcist

The Know-Nothing Party seized control of the Washington National Monument Society and built only a few courses of substandard masonry before being expelled, leaving work stalled for years.

Image source: Know Nothing

The Civil War and its aftermath brought construction to a standstill for roughly two decades, leaving the unfinished stump of the monument standing about 156 feet tall above the National Mall.

Image source: American Civil War

On the centennial of American independence, Congress appropriated $200,000 to complete the monument and transferred responsibility for the project to the Army Corps of Engineers.

Image source: United States Congress

Lt. Col. Thomas Lincoln Casey revised Robert Mills' design, eliminating the costly colonnaded base and simplifying the shaft into a clean, tapering obelisk modeled on classic Egyptian proportions.

Engineers under Casey expanded and reinforced the foundation with massive concrete blocks to ensure it could bear the weight of the completed 555-foot obelisk, then the tallest structure of its kind.

A steam-powered hoist was installed inside the rising shaft to lift workers, materials, and visitors, dramatically speeding construction of the upper sections of the monument.

Image source: Elevator

Marble from a new quarry near Cockeysville, Maryland, differed slightly in tone from the original stone used before the halt, creating the distinctive visible line about one-third up the monument that remains today.

With the capstone in place, the Washington Monument stood 555 feet, 5⅛ inches tall, making it the tallest structure in the world until the Eiffel Tower was completed five years later.

A nine-inch aluminum pyramid, at the time one of the largest pieces of the rare metal ever cast, was placed atop the monument as a lightning rod and crowning finial.

Image source: Aluminium

New floodlights were installed around the base, dramatically improving nighttime illumination of the monument and making it a glowing centerpiece of the capital city.

Management of the monument passed to the National Park Service, which has cared for it ever since as part of the National Mall and Memorial Parks unit.

Repairs were undertaken after minor structural issues emerged, including stabilization work and modernization of the aging elevator systems serving the observation level.

Image source: 1933 Long Beach earthquake

The Washington Monument received official recognition as a National Historic Landmark, affirming its significance as a defining symbol of the American republic.

Image source: National Historic Landmark

In preparation for America's 1976 bicentennial celebrations, extensive cleaning, repointing, and structural repairs restored the weathered exterior of the monument.

Image source: United States Bicentennial

During a major restoration ahead of the millennium, security upgrades included replacing observation windows with bulletproof glass following heightened concerns about terrorism.

A magnitude 5.8 earthquake centered in Virginia cracked stones and damaged the pyramidion near the top of the monument, forcing an indefinite closure to visitors.

Image source: 2011 Virginia earthquake

Engineers repaired more than 150 cracks using scaffolding wrapped around the entire shaft, completing repairs in time for the monument to reopen to the public in May 2014.

After a three-year closure to modernize the elevator and improve security screening facilities, the monument reopened with faster, safer access to its observation deck.