Washington Monument - tallest obelisk and stone structure

The Washington Monument is an obelisk that, at approximately 555 feet tall, is the tallest predominantly stone structure and the tallest obelisk in the world. Constructed of marble, granite, and bluestone gneiss in the 19th century, the monument was completed in 1884 and stands as a singular vertical landmark on the National Mall. It is administered by the National Park Service and remains a distinctive example of 19th-century monumental masonry.