LOOP, THE

35-block area of downtown Chicago, Illinois, U.S. The area was probably so named because elevated railroad tracks form a loop around it; the term is now sometimes used to refer to downtown Chicago generally. The Loop includes a portion of State Street, a major shopping district, with some of the nation's largest department stores, and La Salle Street (often called Chicago's Wall Street), the location of several large financial institutions, including the Chicago Stock Exchange (from 1949 to 1993, the Midwest Stock Exchange) and the Chicago Board of Trade. The Loop was the site of the Home Insurance Building (completed 1885; demolished 1931), generally considered to be the first metal-frame building. Several other buildings constructed during the late 19th century also introduced innovative techniques. Sears Tower, at 1,450 feet (442 metres; see Researcher's Note: Height of the Sears Tower), is among the world's tallest buildings. (See Researcher's Note: Heights of Buildings.)