English: Night-time exterior image of the upper floors of the George Washington Masonic National Memorial in Alexandria, Virginia, in the United States. The structure is capped by a step pyramid with seven steps. The light fixture atop the pyramid is in the shape of a double keystone (a shape which is of symbolic importance to Freemasons).

The Grand Chapter of Virginia of Royal Arch Masonry donated the aluminum double-keystone symbol and light at the top of the building. The fixture, the largest of its kind in the world at the time, was in place by February 1929 but not yet illuminated (as exterior lighting systems were still being installed). The $17,000 light fixture is 19 feet (5.8 m) high, made of aluminum, and has its own independent power supply. Claude Haynes, a steelworker employed as a construction worker at the memorial since 1923 and a member of Alexandria-Washington Lodge No. 22, completed the light by installing the aluminum sheeting on it on February 8, 1929.

The United States Department of Commerce provided, free of charge, equipment for lighting the exterior of the building and tower as an aid to aviation. The memorial's owners paid to have the equipment installed. In 1970, the city of Alexandria donated a back-up electrical generator to keep the exterior of the tower lit in case of blackouts. Additional lighting for the tower was also installed that year. The Grand Lodge of New York provided the funds to finish the work, and the final tower exterior illumination was completed in the summer of 1973.