stadium (stā´dēəm), racecourse in Greek cities where footraces and other athletic contests took place. The name is the Latin form of the Greek word for a standard of length and originally referred merely to the measured length of the course. Usually the stadiums were U-shaped, the curve being opposite the starting point. Natural slopes were used when possible to support the seats. The stadiums at Athens, Olympia, Delphi, and Epidaurus are among the best-known examples. The courses were generally 606 ft 9 in. long (600 Greek ft, or 185 m), although the length varied according to the local variations of the measuring unit. A similar plan was used for the hippodrome, the course where horses raced. The stadium at Athens, which was completely restored to serve for the first modern Olympic games in 1896, dates from 330 BC The great modern revival of interest in athletic contests has produced structures designed for various sports that seat many thousands of spectators. Although many are called stadiums, they are only slightly derivative from those of the Greeks and in most features resemble rather the Roman circuses and amphitheaters. In the United States stadiums have greatly increased in number and perfection since 1914. Their forms vary, being rectangular with curved corners, elliptical, or U-shaped. The modern stadium generally is designed for such sports as football, baseball, and track racing. The stadiums erected in European cities for Olympic games have usually been retained as permanent structures. For the 1960 Olympics in Rome, Pier Luigi Nervi designed two remarkable reinforced-concrete arenas spanned by delicately ribbed roofs. Among American stadiums with large seating capacities are Michigan Stadium at Ann Arbor, 107,000; Ohio Stadium at Columbus, 104,000; Neyland Stadium at Knoxville, Tenn., 103,000; the Rose Bowl at Pasadena, Calif., 97,000; Beaver Stadium at University Park, Pa., 94,000; and the Los Angeles Memorial Coliseum, 92,000. Some capacity estimates vary, as the source may include temporary seating and standing room. A more recent innovation in stadium design is exemplified by the Harris County Domed Stadium, or "Astrodome," in Houston, Tex., which opened in 1965 and was used for baseball and football into the 1990s. The steel-supported structure was the first covered, temperature-controlled arena and has been the basis for many such designs subsequently developed throughout the United States; many more recent enclosed designs have retractable roofs.