The Washington Monument in Washington D.C.

Architect Robert Mills envisioned honoring America's first president, George Washington, with a 600-foot (183 m) tall, square, flat-topped pillar. At the base of the pillar, Robert Mills envisioned an elaborate colonnade with statues of thirty Revolutionary War heroes and a soaring sculpture of George Washington in a chariot.

To build Robert Mills' monument would have cost over a million dollars (more than $21 million in modern dollars). Plans for the colonnade were postponed and eventually eliminated. The Washington Monument evolved into a simple tapered obelisk made of white marble, granite, and sandstone. The pyramid shape of the monument was inspired by ancient Egyptian architecture.

The Civil War and money shortages delayed construction on the Washington Monument. Because of interruptions, the stones are not all the same shade. Part way up, at 150 feet (45 m), the masonry blocks are a slightly different color. Thirty years passed before the monument was completed.

In 1999, the Washington Monument faced extensive renovations. Postmodernist architect Michael Graves surrounded the monument with distinctive scaffolding made from 37 miles of aluminum tubing. The scaffolding took four months to erect and became a tourist attraction in itself.

• About the Washington Monument Scaffolding
• Michael Graves discusses his Washington Monument scaffolding

Facts About the Washington Monument

• Height: 555 feet, 5.125 inches (169.29 m)
• Width at Base: 55 feet, 1½ inches (16.80 m)
• Width at Top of Shaft: 34 feet, 5 inches (10.5 m)
• Thickness of Walls: 15 feet (4.6 m) at base and 18 inches (460 mm)at observation level
• Number of Blocks: 36,491

Learn More About the Washington Monument

• History of the Washington Monument
• Visiting the Washington Monument
• Photos of the Washington Monument