The Washington Monument Walking across the ellipse from the White House, you come upon the Washington Monument. John points out that this is the tallest masonary structure in the world, standing at 555 feet, 5 1/8 inches. It was dedicated in memory of President Washington in 1885. The monument is open daily from 9 a.m. to 5 p.m. (April 1 to Labor Day unil Midnight). Today the elevator seems to be broken.