One prominent civic commission was the seamless extension, to north and south, of the New-York Historical Society building on Central Park West between 76th and 77th Streets, carried out in 1938. York and Sawyer's central block dating from 1908 was extended and sympathetically completed by pavilions on either end. This project stands among the last examples of Beaux-Arts architecture completed in the city and in the entire country. In sharp contrast the firm's most theatrical modernist building came the same year. That was the Electrical Products Building for the 1939 New York World's Fair, where an arch-headed blue slab tower intersected with a stepped curved structure, housing demonstrations of radical new uses of electricity: shaving, mixing cake batter, and home sewing.