shopping center, a concentration of retail, service, and entertainment enterprises designed to serve the surrounding region. The modern shopping center differs from its antecedents—bazaars and marketplaces—in that the shops are usually amalgamated into one encompassing structure. The first modern shopping center, the Country Club Plaza, opened in Kansas City, Mo., in 1922. By 1956, when the first enclosed mall, designed by Victor Gruen, opened in Edina, Minn., a suburb of Minneapolis, about 2,000 shopping centers had been built. The so-called malling of America peaked in the late 1980s and early 1990s, when approximately 60 large malls (more than 400,000 sq ft/37,000 sq m in size) were built annually; over 100 were built annually in some years during that period. In comparison, only about 30 large malls were built in 1998. Shopping centers accounted for about 76% of all nonautomotive retail sales in the United States in 2003.

Of nearly 47,000 shopping centers in the United States, about 1,100 are categorized as enclosed malls, Regional malls contain at least two department stores or "anchor stores" and, depending on population density, attract consumers from within a 20-mi (32 km) radius. Superregional malls, of which about 350 exist, include at least five department stores and 300 shops and may serve an area of up to a 100-mi (160-km) radius. Generally smaller, open-air strip centers, unlike the larger malls, do not usually feature an indoor concourse, although in the 1980s and 90s the construction of enclosed, or all-weather, minimalls began to accelerate. Open-air shopping centers are typically anchored by large grocery stores. Another distinction among shopping centers is location, namely suburban or downtown. In an attempt to revitalize retail sales in central business districts, many large U.S. cities have built so-called festival-marketplaces, which combine shopping, entertainment, and sightseeing. Examples of such centers include Faneuil Hall in Boston, South Street Seaport in New York City, Harborplace in Baltimore, and Ghirardelli Square in San Francisco.

The world's first megamall was the West Edmonton Mall in Alberta, Canada. Long also the world's largest mall at 5.3 million sq ft (493,000 sq m), it was the culmination of the developer's dream of a consumers' and retailers' paradise when it opened (1981-85). The mall contains more than 800 shops, 11 department stores, 110 restaurants, an ice-skating rink, the world's largest indoor water park, 19 movie theaters, a hotel, a chapel, 13 nightclubs, and a replica of Columbus's Santa Maria. Two larger malls, in Beijing and Dongguan, China, began to open in 2004 and 2005 respectively, and more Chinese megamalls are under construction. The largest mall in the United States is the 4.2-million-sq-ft (391,000-sq-m) Mall of America, opened in 1992 in Bloomington, Minn., which features at its center a seven-acre amusement park.

relocation center, in U.S. history, camp in which Japanese and Japanese-Americans were interned during World War II. Fearing a Japanese invasion, the military leaders, under authority of an executive order, defined (Mar., 1942) an area on the West Coast from which all persons of Japanese ancestry were to be excluded. That same month the War Relocation Authority (WRA) was created. After voluntary evacuation was prohibited, the army forcibly moved approximately 110,000 evacuees, most of whom were American citizens, to 10 relocation centers in Western states operated by the authority. Smaller numbers of Germans, Italians, and other nationalities were also interned or forcibly relocated. Although food and shelter were provided and wages were paid to those who wished to work, living conditions were poor, and several riots occurred during the war. Separation of the loyal and disloyal began in July, 1943. Persons who could prove their loyalty and had employment waiting for them were released to live anywhere except in the proscribed area, while those deemed disloyal by the Federal Bureau of Investigation were segregated in the Tule Lake center. The majority of evacuees remained in the relocation centers until after Dec., 1944, when the mass exclusion orders were revoked. The last of the centers, at Tule Lake, was closed in Mar., 1946. The WRA was terminated in 1946. The evacuees suffered property losses estimated at $400 million, and the government was severely criticized for depriving citizens of their civil liberties. In 1988, President Reagan signed a bill that granted the surviving Japanese-American internees a tax-free payment of $20,000 each and an apology from the U.S. government.

day-care center: see day nursery.

center of mass, the point at which all the mass of a body may be considered to be concentrated in analyzing its motion. The center of mass of a sphere of uniform density coincides with the center of the sphere. The center of mass of a body need not be within the body itself; the center of mass of a ring or a hollow cylinder is located in the enclosed space, not in the object itself. Under the action of a constant force of gravity, a body suspended or balanced at its center of mass will be stable; there will be no net moment acting on it. Sometimes a problem may be analyzed from the point of view of the center of mass of an entire system of objects, such as several colliding elementary particles or a multiple-star system. For example, the complex motions of the earth and moon about the sun become somewhat simpler when viewed from the common center of mass of the earth-moon system, located about 1,000 mi (1,600 km) below the earth's surface. It is this point that is moving in an elliptical orbit around the sun rather than the center of mass of the earth alone.

center of gravity: see center of mass.

center, in politics, a party following a middle course. The term was first used in France in 1789, when the moderates of the National Assembly sat in the center of the hall. It can refer to a separate party in a political system, e.g., the Catholic Center party of imperial and Weimar Germany, or to the middle group of a party consisting of several ideological factions.

World Trade Center, former building complex in lower Manhattan, New York City, consisting of seven buildings and a shopping concourse on a 16-acre (6.5-hectare) site; it was destroyed by a terrorist attack on Sept. 11, 2001. Prior to its destruction, the World Trade Center had been the world's largest commercial complex, home to many businesses, government agencies, and international trade organizations. Most prominent among its structures were the 110-story rectangular twin towers, one rising to 1,362 ft (415 m) and the other to 1,368 ft (417 m), with floors roughly an acre in size. Designed by Minoru Yamasaki and Emery Roth, the towers and concourse portion of the center were completed in 1973 at a cost of some $750 million. For a brief period (until the completion of the Sears Tower in Chicago in 1974), the World Trade towers were the tallest buildings in the world. They remained the largest structures on the Eastern Seaboard of the United States, an internationally known landmark and tourist attraction rising high above the skyline of lower Manhattan.

In 1993 a terrorist car-bomb explosion damaged portions of the complex, killing six people and causing more than $300 million in damage. Sheik Omar Abdel Rahman and nine other Islamic extremists were convicted of conspiracy and other charges related to the bombing in 1993, and the so-called mastermind, Ramzi Yousef, was convicted in 1998. On Sept. 11, 2001, a second terrorist attack, in which two hijacked commercial jetliners were crashed into the towers, ignited huge, intense fires in the upper stories of both buildings, weakening them and leading to their collapse. Other structures in the complex were completely or partially destroyed as a result, and many surrounding buildings were severely damaged. More than 2,700 people, including the passengers and crew of the airliners and several hundred emergency personnel responding to the initial fires, lost their lives; more than 7,000 people were injured.

The enormity of the events of Sept. 11 (see also 9/11), which also involved a similar attack with a hijacked jetliner on the Pentagon in Washington, D.C., and the crash in W Pennsylvania of a fourth hijacked plane, galvanized national feeling in the United States, where many watched the events unfold on television. In the aftermath of the worst terrorist attack in history, President George W. Bush announced a war on terrorism, and many nations pledged their support. Al Qaeda, headed by Osama bin Laden, was identified by U.S. authorities as being behind the attacks, and the United States subsequently began military operations in Afghanistan, where bin Laden was based and where the government was closely allied with him.

In Dec., 2001, Zacarias Moussaoui, a Frenchman of Moroccan descent who had been arrested (Aug., 2001) on immigration violations in Minnesota, was indicted on charges that he was part of the conspiracy responsible for the September attacks. He pleaded guilty in 2005 to being part of a conspiracy to attack the White House in a similar manner but denied being part of either Sept. 11 attack, and was given a life sentence in 2006.

The alleged mastermind of the plot was Khalid Sheikh Mohammed, a Kuwaiti of Pakistani parentage who had become a high-ranking member of Al Qaeda. He was captured in Pakistan in 2003, held by the United States at an undisclosed location, and transferred to Guantánamo Bay in 2006. According to a censored transcript of a closed-door hearing in 2007, he admitted to organizing and supervising the execution of the attacks of Sept. 11, but the government also later revealed that he had been subjected to waterboarding, which is generally regarded as a form of torture. In Feb., 2008, the Pentagon announced that a military tribunal would try Mohammed and five others held at Guantánamo on conspiracy and other charges relating to the attacks.

In the aftermath of the center's destruction, many competing interests—the city and state of New York, the owners of the site, the buildings' developer, survivors of the attack and families and friends of those killed, and others—advocated a variety of approaches to rebuilding the site. After a lengthy design competition, a preliminary master construction plan for the site, by Daniel Libeskind, was approved in 2003. The design has since been much modified, and a new overall plan was unveiled in 2006.

Embracing the footprints where the towers once stood, a street-level memorial plaza is planned, with two sunken pools fed by waterfalls; the names of those who died as a result of the attack will be displayed in the plaza, which will also include a World Trade Center Museum. Surrounding the memorial, will be a group of office towers that rise in height toward the the "Freedom Tower" (Tower 1), designed by the American architect David M. Childs of Skidmore, Owings and Merrill. Tower 2 is being designed by England's Lord Norman Foster, Tower 3 by another English architect, Lord Richard Rogers, and Tower 4 by Japan's Fumihiko Maki. The complex will also include a transportation hub by Spain's Santiago Calatrava and a performing arts center to be created by Frank Gehry.

Walter Reed Army Medical Center, major hospital complex in Washington, D. C., and Forest Glen, Md.; est. 1923 and named for U.S. army surgeon Walter Reed. It is composed of seven units including a general hospital and a research institute. There are several thousand beds.

Storm King Art Center, sculpture park and museum located in Mountainville, Orange co., SE N.Y., some 55 mi (89 km) north of New York City. Founded in 1960, it is comprised of 500 acres (202 hectares) of lawns, fields, hills, and forests, which provide a unique backdrop for sculpture, and a Norman-style museum (1935). The center has a large permanent collection of sculpture, much of it displayed on the grounds. Its holdings were mainly created after 1960 and are often monumental in scale and predominantly abstract. The core of the collection is a group of 13 large works by David Smith. Among the other notable works in the collection are those by Barbara Hepworth, Alexander Calder, Louise Nevelson, Isamu Noguchi, Mark di Suvero, Richard Serra, George Ricky, and Kenneth Snelson. Open from April to November, the center holds annual special exhibitions.

Rockefeller Center, complex of buildings in central Manhattan, New York City, between 48th and 51st streets and Fifth Ave. and the Ave. of the Americas (Sixth Ave.). The project was sponsored by John D. Rockefeller, Jr., with fourteen of the buildings built between 1931 and 1939. These include the 70-story GE (General Electric) Building, known prior to 1989 as the RCA (Radio Corp. of America) Building. The Time-Life Building (built 1960-61), the most recent addition to the group, extended the center's boundaries west of the Ave. of the Americas. The buildings house offices, shops, restaurants, exhibition rooms, broadcasting studios, and the opulently Art Deco Radio City Music Hall, New York City's largest theater. Five of the western buildings of Rockefeller Center in the broadcasting and entertainment section are known as Radio City. Many sculptors and painters are represented in the decoration of the buildings and grounds. Paul Manship designed the Prometheus of the central fountain, which overlooks an outdoor skating rink and mall.

Paley Center for Media, American archive of radio and television programs, and forum for the discussion of the role and evolution of electronic media; opened 1976 in New York City as the Museum of Broadcasting, renamed 1990 the Museum of Television and Radio, present name adopted 2007. The center is in effect the first public library devoted to the electronic media, but in addition it sponsors discussions of issues impacting the media. There are three criteria for adding a program to the center's collection: excellence, historical significance, and social impact. A west coast branch, which duplicates the New York branch's entire collection of more than 140,000 television and radio programs and commercials, was opened in Beverly Hills, Calif. in 1996.

Lincoln Center for the Performing Arts, in central Manhattan, New York City, between 62d and 66th streets W of Broadway. Lincoln Center is a complex of many buildings, including the Metropolitan Opera, Avery Fisher Hall, the New York State Theater, the Juilliard School (including Alice Tully Hall for recitals and a chamber music hall), the Vivian Beaumont Theater, the Library-Museum of the Performing Arts, the Guggenheim Bandshell in Damrosch Park, and several Fordham Univ. buildings. A nonprofit organization with municipal support, Lincoln Center is dedicated to the encouragement of new artists and to the presentation of internationally acclaimed performers. The project was constructed between 1959 and 1972. Among those selected to design the buildings were the architects W. K. Harrison, Eero Saarinen, Philip Johnson, and Max Abramowitz, and the stage designer Jo Mielziner. A 28-story tower with dormitory rooms, rehearsal studios, a movie theater, and other facilities was added to the complex in 1991. In 2004 the Center added Frederick P. Rose Hall, designed by Rafael Viñoly and located at the nearby Time Warner Center, to house its jazz division. Lincoln Center is comprised of 11 constituent organizations. They are the Chamber Music Society of Lincoln Center, the Film Society of Lincoln Center, Jazz at Lincoln Center, the Juilliard School, the Lincoln Center Theater, the Metropolitan Opera, the New York City Ballet, the New York City Opera, the New York Philharmonic-Symphony Orchestra, the New York Public Library for the Performing Arts, and the School of American Ballet.

International Center for Settlement of Investment Disputes (ICSID), specialized agency of the United Nations. A member of the World Bank Group (see International Bank for Reconstruction and Development), it was formed in 1966 and has its headquarters in Washington, D.C. In an effort to help promote increased flows of international investment, ICSID assists in the mediation or conciliation of investment disputes between governments and private foreign investors. Participation in such arbitration is voluntary. Normally the parties are among the agency's 148 member states or citizens of those states, but in special circumstances nonparticipating states or individuals from such states may be accepted as mediating parties. An autonomous international organization, ICSID has close links with the World Bank; it operates through both an administrative council, chaired by the World Bank's president, and a secretariat.

Getty Center, art museum complex in Brentwood, Calif., operated by the J. Paul Getty Trust. It consists of six buildings on 124 acres (50 hectares) located on a spectacular promontory overlooking Los Angeles. Designed by architect Richard Meier, the center opened in 1997. The museum houses the Getty collections of European paintings, drawings, sculpture, illuminated manuscripts, and decorative arts as well as European and American and European photographs. The complex also includes a research library and archives, which includes performance and lecture facilities; conservation and art historical institutes; and educational and computer centers. The first Getty Museum was located at J. Paul Getty's home in Malibu; the second was a Roman-style villa in Malibu that opened in 1974 and now exhibits the Getty's outstanding collection of classical antiquities and serves as a center for comparative archaeology and cultures.

European Space Research and Technology Center (ESTEC): see European Space Agency.

European Space Operations Center (ESOC): see European Space Agency.

European Astronaut Center (EAC): see European Space Agency.

Brooklyn Center, city (1990 pop. 28,887), Hennepin co., SE Minn., a residential suburb of Minneapolis; inc. 1911. It has light industry and has been marked by suburban and economic growth since the 1970s.

Atlanta University Center, at Atlanta, Ga.; coeducational. The largest consortium of historically African-American educational institutions in the country, it was organized in 1929 when three schools—Atlanta Univ. (chartered 1867), Morehouse College (1867), and Spelman College (1881)—became affiliated in a university plan. Atlanta Univ. was to be devoted exclusively to graduate education, with the other two colleges providing undergraduate programs. Later Clark College (chartered 1877), Interdenominational Theological Center (1958), Morehouse School of Medicine (1982), and Morris Brown College (1885) also joined the university center's affiliation agreement. In 1988 Clark College and Atlanta Univ. merged to form Clark Atlanta Univ., which is still part of the university center.

Grouping of municipal facilities in a limited precinct often adjacent to the central business district of a city. The civic center is based on both the Greek acropolis and the Roman forum. The plan includes the city hall and adjoining park or plaza, headquarters for city departments, courthouses, and often a post office, public-utility offices, public health facilities, and government offices.

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Complex formerly consisting of seven buildings around a central plaza, near the southern tip of Manhattan. Its huge twin towers (completed 1970–72) were designed by Minoru Yamasaki (1912–86). At 1,368 ft (417 m) and 1,362 ft (415 m) tall, they were the world's tallest buildings until surpassed in 1973 by the Sears Tower in Chicago. The towers were notable for the relationship of their simple, light embellishment to their underlying structure. In 1993 a bomb planted by terrorists exploded in the underground garage, killing several people and injuring some 1,000. A much more massive attack occurred on Sept. 11, 2001, when first One World Trade Center and then Two World Trade Center were struck by hijacked commercial airliners that were deliberately flown into them. Shortly thereafter both of the heavily damaged towers, as well as adjacent buildings, collapsed into enormous piles of debris. The attacks claimed the lives of some 2,750 people. Thousands more were injured. See September 11 attacks.

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Complex of 14 limestone skyscrapers set amid a series of outdoor spaces on a 12-acre (5-hectare) site, built between 1929 and 1940 in midtown Manhattan. It was designed by a team of architects headed by Henry Hofmeister, H. W. Corbett, Raymond Hood, and Wallace K. Harrison. Wood veneering, mural painting, mosaics, sculpture, metalwork, and other allied arts were integrated with the architecture. Radio City Music Hall (1932) is noted for its Art Deco interior.

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