Wall, Richard, 1694-1778, Spanish statesman. Born in France of Irish parents, Wall entered the Spanish military service as a young man and later held important diplomatic posts. He helped negotiate the Treaty of Aix-la-Chapelle (1748) ending the War of the Austrian Succession, and he cemented friendly Anglo-Spanish relations as ambassador in London (1748-52). In Madrid, he served (1752-64) as minister of state under Ferdinand VI and Charles III.

wall, in architecture, protective, enclosing, or dividing vertical structure. Its thickness is determined by the material, height, and stress. It may be of studding and lath, either boarded or plastered; adobe; rammed earth; brickwork or stonework; concrete; tile; or of steel in combination with one or more of the preceding materials. The wall serves two functions. A bearing wall is used as a support, e.g., for the floors and roof. Usually raised on foundations, it is thicker at the bottom than at the top and is often buttressed. A nonbearing wall, such as a partition screen or curtain wall, is used to separate and define spaces and is generally much thinner. A party wall is one common to two adjoining buildings, and a gable wall is one at right angles to the roof ridge. A fire wall, or bulkhead, separates hazardous equipment from the rest of a structure to prevent the spreading of fire; in ships the bulkhead is also watertight. The front wall or face of a building is termed the facade. Exterior walls may be finished with stucco or graffito and enhanced by bas-relief, tile, mosaic, or painted decoration. Arcade, rustication, and vermiculated work are means of ornamenting brick and stone masonry. In engineering a retaining wall either of Cyclopean or of wet masonry protects an embankment from washing; a sea wall, or breakwater, is for harbor protection; and a dam is an earth, masonry, or concrete wall to stop the natural flow of a stream to conserve a water supply or create power. The defensive walls of a city or other political division (see Great Wall of China) are frequently two or three concentric ramparts, often including fortification and watchtowers. Great portals form the gateways. Notable walls of antiquity were those of Thebes, Troy, Jericho, and Babylon; an example of a medieval wall is that at Carcassonne in France.

Painting applied to and made integral with the surface of a wall or ceiling. Its roots can be found in the universal desire that led prehistoric peoples to create cave paintings—the desire to decorate their surroundings and express their ideas and beliefs. The Romans produced large numbers of murals in Pompeii and Ostia, but mural painting (not synonymous with fresco) reached its highest degree of creative achievement in Europe with the work of such Renaissance masters as Masaccio, Fra Angelico, Leonardo da Vinci, Michelangelo, and Raphael. In the 20th century, the mural was embraced by artists of the Cubist and Fauve movements in Paris, revolutionary painters in Mexico (e.g., Diego Rivera, José Clemente Orozco, David Alfaro Siqueiros), and Depression-era artists under the sponsorship of the U.S. government (e.g., Ben Shahn, Thomas Hart Benton).

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Any of various upright constructions used to divide or enclose a room or building. In traditional masonry construction, bearing walls supported the weight of floors and roofs, but modern steel and reinforced-concrete frames, as well as heavy timber and other skeletal structures, require exterior walls only for shelter. Some urban buildings dispense with walls on the ground floor, extending outdoor plazas under the building and permitting easier access to elevators, escalators, and stairs. In masonry construction, all types of floors and roofs except domes are most easily supported on straight, parallel walls. Nonbearing walls, used when loads are carried by girders, beams, or other members, can be either curtain walls or infill of brick, block, or other material. Seealso cavity wall, retaining wall, shear wall.

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or revetment

Wall constructed to hold in place a mass of earth or prevent the erosion of an embankment. It may also be battered, with the face inclined toward the load it is bearing. The most basic type of reinforced retaining wall is the massive concrete gravity wall, which is prevented from falling over by the sheer weight and volume of its mass. A cantilever (L-shaped) retaining wall resists overturning by means of cantilever footings, spread footings (see foundation) shaped to resist overturning and sliding.

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Street in New York City where many major U.S. financial institutions are located. The street, in southern Manhattan, is narrow and short and extends only about seven blocks from Broadway to the East River. It was named for an earthen wall built by Dutch settlers in 1653 to repel an expected English invasion. Even before the Civil War it was recognized as the nation's financial capital, and it remains a worldwide symbol of high finance. The Wall Street, or financial, district contains the New York Stock Exchange, the American Stock Exchange, and the Federal Reserve Bank of New York. The district is also the headquarters for many investment banks, securities dealers, utilities and insurance companies, and brokerage firms.

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Continuous Roman defensive barrier. Begun by Hadrian in AD 122, the wall guarded the northwestern frontier of the province of Britain from barbarian (particularly Celtic) invaders. It extended 73 mi (118 km) from coast to coast, from Wallsend (Segedunum) to Bowness. It had towers, gates, and forts at regular intervals; a ditch fronted it and an earthwork (the vallum) ran behind it. It was briefly abandoned in favour of the Antonine Wall, but it returned to use until circa 410. Portions remain visible today.

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Chinese Wanli Changcheng

Defensive wall, northern China. One of the largest building-construction projects ever carried out, it runs (with all its branches) about 4,500 mi (7,300 km) east to west from the Bo Hai (Gulf of Chihli) to a point deep in Central Asia. Large parts of the fortification date from the 7th to the 4th century BC. In the 3rd century BC the emperor Shihuangdi connected existing defensive walls into a single system fortified by watchtowers. These served both to guard the rampart and to communicate with the capital, Xianyang (near modern Xi'an) by signal—smoke by day and fire by night. Originally constructed partly of masonry and earth, it was faced with brick in its eastern portion. It was rebuilt in later times, especially in the 15th and 16th centuries. The basic wall is about 23–26 ft (7–8 m) high; at intervals towers rise above it to varying heights. It was designated a UNESCO World Heritage site in 1987.

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Barrier surrounding West Berlin that closed off East Germans access to West Berlin from 1961 to 1989 and served as a symbol of the Cold War's division of East and West Germany. The barrier was built in response to the flight of about 2.5 million East Germans to West Germany in the years 1949–61. First erected on the night of Aug. 12–13, 1961, it developed into a system of concrete walls topped with barbed wire and guarded with watchtowers, gun emplacements, and mines. It was opened in the 1989 democratization that swept through eastern Europe and has been largely torn down.

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A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air. There are three principal types of structural walls: building walls, exterior boundary walls, and retaining walls.

Building walls

Building walls have two main purposes: to support roofs and ceilings, and to divide space, providing security against intrusion and weather. Such walls most often have three or more separate components. In today's construction, a building's wall will usually have the structural elements (such as 2×4 studs in a house wall), insulation, and finish elements, or surface (such as drywall or panelling). In addition, the wall may house various types of electrical wiring or plumbing. Electrical outlets are usually mounted in walls.

Building walls frequently become works of art externally and internally, such as when featuring mosaic work or when murals are painted on them; or as design foci when they exhibit textures or painted finishes for effect.

On a ship, the walls separating compartments are termed "bulkheads", whilst the thinner walls separating cabins are termed "partitions".

In architecture and civil engineering, the term curtain wall refers to the facade of a building which is not load-bearing but functions as decoration, finish, front, face, or history preservation.

Boundary walls

Boundary walls include privacy walls, boundary-marking walls on property, and city walls. These intergrade into fences; the conventional differentiation is that a fence is of minimal thickness and often is open in nature, while a wall is usually more than a nominal thickness and is completely closed, or opaque. More to the point, if an exterior structure is made of wood or wire, it is generally referred to as a fence, while if it is made of masonry, it is considered a wall. A common term for both is barrier, convenient if it is partly a wall and partly a fence, for example the Berlin Wall. Another kind of wall/fence ambiguity is the ha-ha which is set below ground level, so as not to interrupt a view yet acting as a barrier to cattle for example.

Before the invention of artillery, many European cities had protective walls. In fact, the English word "wall" is derived from Latin vallum, which was a type of fortification wall. Since they are no longer relevant for defense, the cities have grown beyond their walls, and many of the walls have been torn down. Extreme examples of boundary walls include the Great Wall of China and Hadrian's Wall. A modern functional example was the Berlin Wall, which divided Germany.

Retaining walls

In areas of rocky soils around the world, farmers have often pulled large quantities of stone out of their fields to make farming easier, and have stacked those stones to make walls that either mark the field boundary, or the property boundary, or both.

Retaining walls are a special type of wall, that may be either external to a building or part of a building, that serves to provide a barrier to the movement of earth, stone or water. The ground surface or water on one side of a retaining wall will be noticeably higher than on the other side. A dike is one type of retaining wall, as is a levee, a load-bearing foundation wall, and a sea wall.

Shared walls

Special laws often govern walls shared by neighboring properties. Typically, one neighbor cannot alter the common wall if it is likely to affect the building or property on the other side.

Etymology

It is notable that English uses the same word to refer to an external wall, and the internal sides of a room. This is by no means universal, and many languages distinguish between the two. In German, some of this distinction can be seen between Wand and Mauer.

Walls in Popular Culture

• Progressive/psychedelic rock band Pink Floyd have a concept album called The Wall. This Wall is not real, but a metaphor for social barring.
• Social networking site Facebook uses a wall to log the scrawls of friends. Users have gone onto create more advanced versions of the original wall, such as the application SuperWall.

See also

• List of walls
• Ashlar
• Curtain wall
• Dry-stone wall
• Fence
• Load-bearing wall
• Sleeper wall
• Stone wall
• Wallpaper
• As mentioned above, The Wall is an album by progressive/psychedelic rock band Pink Floyd.