Classicly

Architect for the National Gallery was John Russell Pope, who also designed the Jefferson Memorial and other outstanding public buildings in Washington. The building is one of the largest marble structures in the world, measuring 780 feet in length and containing more than 500,000 square feet of interior floor space. The exterior is of rose-white Tennessee marble. The columns in the Rotunda were quarried in Tuscany, Italy. Green marble from Vermont and gray marble from Tennessee were used for the floor of the Rotunda. The interior walls are of Alabama Rockwood stone, Indiana limestone, and Italian travertine. The entire building is air-conditioned and humidity-controlled throughout the year to maintain the optimum atmospheric conditions for the works of art it contains.