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Underground City (Beijing)
The Underground City () is a Cold War era bomb shelter consisting of a network of tunnels located beneath Beijing, China. It has also been referred to as the Underground Great Wall since it was built for the purpose of military defense. The complex was constructed from 1969 to 1979 in anticipation of a nuclear war with the Soviet Union, as Sino-Soviet relations worsenedJiang, Steven.Beijing Journal: An underground 'parallel universe'. Cable News Network (2008-02-01). Retrieved on 2008-07-14.Wang, Zhiyong.. China Internet Information Center (2005-04-15). Retrieved on 2008-07-14. and was officially reopened in 2000. Visitors were allowed to tour portions of the complex,
. Beijing China Tourist Information and Travel Guide. Retrieved on 2008-07-14.
which has been described as "dark, damp, and genuinely eerie".
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Zhenbao Island
Zhenbao Island () or Damansky Island (russian: о́стров Дама́нский, ''ostrov Damanskiy'') is an island with an area of only . It is on the Ussuri River on the border between Primorsky Krai, Russia, and Heilongjiang Province, China. Prior to the 1991 Sino-Soviet Border Agreement, the island was disputed between China and the Soviet Union. It got its Russian name from the railway engineer Stanislav Damansky, who died there in an incident in 1888 while he was charting the future route for the Trans-Siberian railway. Conflict between Soviet Union and China The island was the subject of a territorial dispute between the Soviet Union and China. Battles were fought with a considerable loss of life during the Sino-Soviet border conflict in March 1969. The dispute over Zhenbao raised concerns that it could ignite World War III until an initial resolution of the conflict in November 1969. On 19 May 1991, both sides came to an agreement that the island was part of th ...
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Trapdoor
A trapdoor is a sliding or hinged door in a floor or ceiling. It is traditionally small in size. It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has grown over time. The trapdoor has played a pivotal function in the operation of the gallows, cargo ships, trains booby traps,and more recently theatre and films. History Originally, trapdoors were sack traps in mills, and allowed the sacks to pass up through the mill while naturally falling back to a closed position. Many buildings with flat roofs have hatches that provide access to the roof. On ships, hatches—usually not flush, and never called trapdoors—provide access to the deck. Cargo ships, including bulk carriers, have large hatches for access to the holds. Gallows Most 19th- and early 20th-century gallows featured a trapdoor, usually with two flaps. The victim will be placed at the join. The edge of a trapdoor farthest from the hinge accelerates faster than gravity, so ...
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Ventilation Shaft
In subterranean civil engineering, ventilation shafts, also known as airshafts or vent shafts, are vertical passages used in mines and tunnels to move fresh air underground, and to remove stale air. In architecture, an airshaft is a small, vertical space within a tall building which permits ventilation of the building's interior spaces to the outside. The floor plan of a building with an airshaft is often described as a "square donut" shape. Alternatively, an airshaft may be formed between two adjacent buildings. Windows on the interior side of the donut allow air from the building to be exhausted into the shaft, and, depending on the height and width of the shaft, may also allow extra sunlight inside. See also * Ventilation (architecture) * Stack effect * Underground mine ventilation * Courtyard * Lightwell * Skylight * Atrium (architecture) In architecture, an atrium (plural: atria or atriums) is a large open-air or skylight-covered space surrounded by a building. Atria ...
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Ventilation (architecture)
Ventilation is the intentional introduction of outdoor air into a space. Ventilation is mainly used to control indoor air quality by diluting and displacing indoor pollutants; it can also be used to control indoor temperature, humidity, and air motion to benefit thermal comfort, satisfaction with other aspects of indoor environment, or other objectives. The intentional introduction of outdoor air is usually categorized as either mechanical ventilation, natural ventilation, or mixed-mode ventilation (hybrid ventilation). * Mechanical ventilation is the intentional fan driven flow of outdoor air into a building. Mechanical ventilation systems may include supply fans (which push outdoor air into a building), exhaust fans (which draw air out of building and thereby cause equal ventilation flow into a building), or a combination of both. Mechanical ventilation is often provided by equipment that is also used to heat and cool a space. * Natural ventilation is the intentional passive fl ...
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Water Wells
A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be Aquifer storage and recovery, injected back into the aquifer through the well. Wells were first constructed at least eight thousand years ago and historically vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, and the stepwells and Sakia, sakiehs of India. Placing a lining in the well shaft helps create stability, and linings of wood or wickerwork date back at least as far as the Iron Age. Wells have traditionally been sunk by hand digging, as is still the case in rural areas of the developing world. These wells are inexpensive and low-tech a ...
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Farm
A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used for specialized units such as arable farms, vegetable farms, fruit farms, dairy, pig and poultry farms, and land used for the production of natural fiber, biofuel and other commodities. It includes ranches, feedlots, orchards, plantations and estates, smallholdings and hobby farms, and includes the farmhouse and agricultural buildings as well as the land. In modern times the term has been extended so as to include such industrial operations as wind farms and fish farms, both of which can operate on land or sea. There are about 570 million farms in the world, most of which are small and family-operated. Small farms with a land area of fewer than 2 hectares operate about 1% of the world's agricultural land, and family farms comprise about ...
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Roller Skating
Roller skating is the act of traveling on surfaces with roller skates. It is a recreational activity, a sport, and a form of transportation. Roller rinks and skate parks are built for roller skating, though it also takes place on streets, sidewalks, and bike paths. Roller skating originated in the performing arts in the 18th century. It gained widespread popularity starting in the 1880s. Roller skating was very popular in the United States from the 1930s to the 1950s, then again in the 1970s when it was associated with disco music and roller discos. During the 1990s, inline outdoor roller skating became popular. Sport roller skating includes speed skating, roller hockey, roller derby, figure skating and aggressive quad skating. History The earliest roller skates known are from 18th century Europe. These skates were used in theater and musical performances, possibly to simulate ice skating onstage. Early roller skating was done in a straight line because turning or curvin ...
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Factories
A factory, manufacturing plant or a production plant is an industrial facility, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another. They are a critical part of modern economic production, with the majority of the world's goods being created or processed within factories. Factories arose with the introduction of machinery during the Industrial Revolution, when the capital and space requirements became too great for cottage industry or workshops. Early factories that contained small amounts of machinery, such as one or two spinning mules, and fewer than a dozen workers have been called "glorified workshops". Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production. Large factories tend to be located with access to multiple modes of transportation, some having rail, highway and water loading ...
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Theaters
Theatre or theater is a collaborative form of performing art that uses live performers, usually actors or actresses, to present the experience of a real or imagined event before a live audience in a specific place, often a stage. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music, and dance. Elements of art, such as painted scenery and stagecraft such as lighting are used to enhance the physicality, presence and immediacy of the experience. The specific place of the performance is also named by the word "theatre" as derived from the Ancient Greek θέατρον (théatron, "a place for viewing"), itself from θεάομαι (theáomai, "to see", "to watch", "to observe"). Modern Western theatre comes, in large measure, from the theatre of ancient Greece, from which it borrows technical terminology, classification into genres, and many of its themes, stock characters, and plot elements. Theatre artist Patrice Pavi ...
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Schools
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some schooling to very young children (typically ages 3–5). University, vocational school, college or seminary may be availabl ...
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Clinics
A clinic (or outpatient clinic or ambulatory care clinic) is a health facility that is primarily focused on the care of outpatients. Clinics can be privately operated or publicly managed and funded. They typically cover the primary care needs of populations in local communities, in contrast to larger hospitals which offer more specialised treatments and admit inpatients for overnight stays. Most commonly, the English word clinic refers to a general practice, run by one or more general practitioners offering small therapeutic treatments, but it can also mean a specialist clinic. Some clinics retain the name "clinic" even while growing into institutions as large as major hospitals or becoming associated with a hospital or medical school. Etymology The word ''clinic'' derives from Ancient Greek ''klinein'' meaning to slope, lean or recline. Hence ''klinē'' is a couch or bed and ''klinikos'' is a physician who visits his patients in their beds. In Latin, this became ''cl ...
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