The Washington Monument in Washington, DC. The Washington Monument honors and memorializes George Washington, the first president of the United States. The memorial is 555 feet, 5.125 inches tall, and was the tallest building in the world when it was completed in 1884.

The Washington Monument in Washington, D.C., is the iconic monument that stands at a height of 555 feet (specifically 555 feet, 5 ⅛ inches). Completed in 1884 to honor George Washington, the United States' first president, it was the tallest structure in the world upon its completion until it was surpassed by the Eiffel Tower in 1889. The structure is a classic Egyptian-style obelisk made of marble, granite, and bluestone gneiss. A unique visual feature of the monument is the slight change in the color of the stones about 150 feet up; this "ring" marks where construction was halted for 25 years due to the American Civil War and a lack of funds. When construction resumed, the marble was sourced from a different quarry, leading to the distinct color variation visible today. Visitors can take an elevator to the observation deck at the 500-foot level, which offers panoramic views of the National Mall, the Lincoln Memorial, and the U.S. Capitol. It remains the tallest stone structure and the tallest obelisk in the world, serving as a centerpiece of the American capital's skyline.