One fascinating fact about the Washington Monument is that it is a "two-toned" obelisk due to a 22-year pause in construction. If you look closely at the 152-foot mark, you can see a distinct change in the color of the Maryland marble; construction was halted in 1854 due to a lack of funds and the onset of the Civil War, and when it resumed in 1876, the original quarry had been exhausted, forcing builders to use stone from a different source. A second "high-value" fact is that it remains the world’s tallest stone structure and the world's tallest obelisk, standing at roughly 555 feet. Remarkably, the 91,000-ton monument is held together entirely by gravity and friction; no mortar was used to bind the massive marble blocks. Instead, the sheer weight of the stones ensures the structure's stability, making it an engineering marvel that has survived earthquakes and hurricanes for over 140 years.