The U.S. Capitol Building in Washington, D.C., is perhaps the most significant and architecturally imposing building in the nation. The centerpiece of Capitol Hill and the National Mall, the building sits on a plateau 88 feet above the Potomac River. It houses the legislative branch of United States federal government, consisting of the House of Representatives and the Senate, which collectively create the laws that govern the nation. The building has a rich history dating back to 1791, when President George Washington selected the area that was formerly the part of the state of Maryland, in accordance with the “Residence Act” passed by Congress. On September 18, 1793, President Washington laid the cornerstone for building. Since then, it has been through many construction phases. Dr. William Thornton, whose design for the Capitol was selected after a national architectural competition, is regarded as the first Architect of the Capitol. The construction gradually continued under a series of architects including Stephen Hallet, George Hadfield, and James Hoban – who completed the Senate wing in 1800. By 1811, Benjamin Henry Latrobe, a famous architect of early 19th-century America, renovated the Senate wing and completed the House wing. During the War of 1812, British troops set fire to the building - on August 24, 1814. It was then repaired under the direction of Latrobe in 1815. Three years later, a Boston architect named Charles Bulfinch was appointed to continue the restoration works. He redesigned the central section and developed the landscaping. As the number of senators and representatives grew, a competition was held offering $500 for the best plan to expand the Capitol. Accordingly, Thomas U. Walter was commissioned to design and build the present structure. He added grandiose new House and Senate wings of white marble to the original sandstone building, by 1859. In 1868, the work on the dome and extensions were completed under the supervision of Edward Clark, during whose tenure considerable modernization occurred. As a result of a fire in November 1898, Elliot Woods, Clark's successor, fireproofed the damaged wing. In 1960, 102 more rooms were added to the East front extension, under the direction of J. George Stewart. Presently, the Capitol covers an extensive ground area of 175,170 square feet, with a floor area of nearly 16.5 acres. It serves as an example of American art and history, apart from its use by Congress. A fine example of the 19th-century neoclassical architecture, the Capitol Building’s interior is dominated by Greek and Roman designs, and contains a profusion of frescoes, murals, and statuary by world-renowned artists. Further, it has five floors, of which the first level contains committee rooms and spaces allocated to various congressional officers. The Chambers of the House of Representatives, in the south wing, and the Senate, in the north wing, as well as the offices of the congressional leadership, are on the second floor. Both wings meet at the Rotunda, under a grand, fireproof, cast-iron dome, topped with Thomas Crawford's colossal statue. The dome is famed for its odd acoustic sounds. The Natural Sanctuary Hall, beneath the dome, preserves some of the nation's most important paintings and sculptures. A fresco known as “The Apotheosis of Washington” can be seen above the dome. The third floor is occupied by offices, committee rooms, and press galleries. It also provides access to galleries, from where one can watch the proceedings of the House and the Senate when Congress is in session. Machinery rooms, workshops, and other support areas are on the fourth floor. The building’s grounds also encompass congressional office buildings, the Library of Congress, the Supreme Court building, the U.S. Botanic Garden, the Capitol power plant, and a host of other facilities.