The Monument is an engineering marvel. The Washington Post recently pointed out an interesting fact in an on-going debate about the Monument as the world's tallest free-standing masonry structure. The Monument's marble blocks are held together by just gravity and friction, and no mortar was used in the process.

Yes, the Washington Monument is a free-standing masonry structure, meaning it stands entirely by its own weight and the precision of its construction without the use of an internal steel or concrete skeleton for support. It is, in fact, the world's tallest free-standing stone structure, rising 555 feet 5-1/8 inches (169 meters) above the National Mall. Completed in 1884, it is built from a combination of marble, granite, and bluestone gneiss. The walls are 15 feet thick at the base and taper to 18 inches at the very top. Its stability comes from its massive weight—approximately 91,000 tons—and its foundation, which was significantly reinforced after the first phase of construction to prevent the monument from sinking or leaning. While modern skyscrapers use steel frames to resist wind and seismic forces, the Washington Monument relies on the compressive strength of the stones and its perfectly engineered "obelisk" shape. In 2026, it remains an engineering marvel of the 19th century, standing as a permanent testament to the structural integrity of pure masonry.