Memorial  that represents the first 150 years of the  history of the United States  of America with 60-foot (18 m) sculptures  of the heads of former  United States presidents  (left to right):  George Washington  (1732–1799),  Thomas Jefferson  (1743–1826),  Theodore Roosevelt  (1858–1919), and  Abraham Lincoln  (1809–1865). [ 1 ]  The entire memorial covers 1,278.45 acres (5.17 km