Inscribed on the aluminum cap, notable names and dates in the monument's construction are recalled, and on the east face, facing the rising sun, the Latin words Laus Deo, which translate to, Praise be to God.

At the very peak of the Washington Monument sits a small, nine-inch-tall pyramid made of aluminum. When the monument was completed in 1884, aluminum was a rare and precious metal, valued similarly to silver because it was extremely difficult to extract. This "pyramidion" was intended to serve as a lightning rod to protect the structure from the frequent storms in D.C. Engraved on the four sides of this aluminum cap are inscriptions in Latin, with the most famous being "Laus Deo," which translates to "Praise be to God." In addition to the aluminum cap, the very top is surrounded by several small, blunt lightning rods (added later for better protection) and a series of aircraft warning lights that are integrated into the marble to ensure the 555-foot structure is visible to pilots at night. During the "America 250" celebrations in 2026, the top of the monument has been the focus of high-tech light projections, but the historic aluminum cap remains the permanent crown of this iconic tribute to the first U.S. President.