Editing Clock tower

{{Short description|Architectural structure housing a clock}}
{{Other uses|Clock Tower (disambiguation)}}

[[File:Elizabeth Tower 2014-09-21 205MP.jpg|thumb|upright=.85|[[Big Ben]] in [[London]] is a major landmark.]]
'''Clock towers''' are a specific type of structure that house a [[turret clock]] and have one or more [[clock face]]s on the upper exterior walls. Many clock towers are freestanding structures but they can also adjoin or be located on top of another building. Some other buildings also have clock faces on their exterior but these structures serve other main functions.

Clock towers are a common sight in many parts of the world with some being iconic buildings. One example is the [[Elizabeth Tower]] in London (usually called "[[Big Ben]]", although strictly this name belongs only to the bell inside the tower).

==Definition==
[[File:Helsinki Bahnhof Uhrturm.JPG|upright=.85|thumb|A clock tower in the [[Helsinki Central Station]]]]
There are many [[structures]] that may have clocks or clock faces attached to them and some structures have had clocks added to an existing structure. According to the [[Council on Tall Buildings and Urban Habitat]] a structure is defined as a building if at least fifty percent of its height is made up of floor plates containing habitable floor area. Structures that do not meet this criterion, are defined as [[towers]]. A clock tower historically fits this definition of a tower and therefore can be defined as any tower specifically built with one or more (often four) [[clock]] [[Clock face|faces]] and that can be either freestanding or part of a [[church (building)|church]] or municipal building such as a [[town hall]]. Not all clocks on buildings therefore make the building into a clock tower.

The mechanism inside the tower is known as a [[turret clock]]. It often marks the hour (and sometimes segments of an hour) by sounding large [[bell (instrument)|bells]] or [[chime (bell instrument)|chime]]s, sometimes playing simple musical phrases or tunes. Some clock towers were previously built as [[Bell towers]] and then had clocks added to them. As these structures fulfil the definition of a tower they can be considered to be clock towers.

==History==
[[File:Tower of the Winds.jpg|thumb|left|The [[Tower of the Winds]] in [[Athens]], built {{Circa|50 BC}} during [[Roman Greece]]]]
Although clock towers are today mostly admired for their aesthetics, they once served an important purpose. Before the middle of the twentieth century, most people did not have watches, and prior to the 18th century even home clocks were rare. The first [[clock]]s did not have faces, but were solely [[striking clock]]s, which sounded bells to call the surrounding community to work or to prayer. They were therefore placed in towers so the bells would be audible for a long distance. Clock towers were placed near the centres of towns and were often the tallest structures there. As clock towers became more common, the designers realized that a [[Clock face|dial]] on the outside of the tower would allow the townspeople to read the time whenever they wanted.

The use of clock towers dates back to [[Ancient history|antiquity]]. The earliest clock tower was the [[Tower of the Winds]] in [[Athens]], which featured eight [[sundial]]s and was created in the 1st century BC during the period of [[Roman Greece]]. In its interior, there was also a [[water clock]] (or clepsydra), driven by water coming down from the [[Acropolis, Athens|Acropolis]].<ref>{{cite journal |last1=Noble |first1=Joseph V. |last2=de Solla Price |first2=Derek J. |title=The Water Clock in the Tower of the Winds |journal=[[American Journal of Archaeology]] |date=1968 |volume=72 |issue=4 |pages=345–355 (353) |doi=10.2307/503828 |jstor=503828 |s2cid=193112893 }}</ref>

[[File:Villard de honnecourt skizze turm.gif|thumb|right|upright=.70|Presumably the first depiction of a medieval central European clock tower (without the actual [[turret clock]]) in the 13th century by [[Villard de Honnecourt]]]]

In [[Song dynasty]] [[History of China|China]], an [[astronomical clock]] tower was designed by [[Su Song]] and erected at [[Kaifeng]] in 1088, featuring a liquid [[escapement]] mechanism.<ref>Bodde, Derk (1991), ''Chinese Thought, Society, and Science'', Honolulu: University of Hawaii Press, p. 140.</ref> In England, a clock was put up in a clock tower, the medieval precursor to [[Big Ben]], at [[City of Westminster|Westminster]], in 1288;<ref name="Britannica">Clocks, ''Encyclopædia Britannica'' 5, 835 (1951).</ref><ref>Frederick Tupper, Jr., 'Anglo-Saxon Dæg-Mæl', ''Publications of the Modern Language Association of America'', Vol. 10, No. 2 (1895), p. 130, citing ''Archæologia'', v, 416.</ref> and in 1292 a clock was put up in [[Canterbury Cathedral]].<ref name="Britannica" /> The oldest surviving turret clock formerly part of a clock tower in Europe is the [[Salisbury Cathedral clock]], completed around 1390. A clock put up at [[St. Albans]], in 1326, 'showed various astronomical phenomena'.<ref name="Britannica" />

[[Al-Jazari]] of the [[Artuqid dynasty]] in [[Upper Mesopotamia]] constructed an elaborate clock called the "castle clock" and described it in his ''Book of Knowledge of Ingenious Mechanical Devices'' in 1206. It was about {{convert|3.3|m|ft|abbr=off}} high, and had multiple functions alongside [[timekeeping]]. It included a display of the [[zodiac]] and the solar and lunar paths, and a pointer in the shape of the [[Crescent|crescent moon]] that travelled across the top of a [[gate]]way, moved by a hidden [[cart]] and causing automatic doors to open, each revealing a [[mannequin]], every hour.<ref>Howard R. Turner (1997), ''Science in Medieval Islam: An Illustrated Introduction'', p. 184. [[University of Texas Press]], {{ISBN|0-292-78149-0}}.</ref><ref>[[Donald Routledge Hill]], "Mechanical Engineering in the Medieval Near East", ''Scientific American'', May 1991, p. 64-69. ([[cf.]] [[Donald Routledge Hill]], [http://home.swipnet.se/islam/articles/HistoryofSciences.htm Mechanical Engineering] {{webarchive |url=https://web.archive.org/web/20071225091836/http://home.swipnet.se/islam/articles/HistoryofSciences.htm |date=December 25, 2007 }})</ref> It was possible to re-program the length of [[Daytime (astronomy)|day]] and [[night]] daily in order to account for the changing lengths of day and night throughout the year, and it also featured five [[robot]]ic musicians who automatically play music when moved by [[lever]]s operated by a hidden [[camshaft]] attached to a [[water wheel]].

Line (mains) synchronous tower clocks were introduced in the United States in the 1920s.

==Landmarks==
Some clock towers have become famous landmarks. Prominent examples include [[Big Ben|Elizabeth Tower]] built in 1859, which houses the [[Big Ben#Great Bell|Great Bell]] (generally known as ''Big Ben'') in [[London]],<ref name="BigBen">{{cite web |url= http://www.parliament.uk/bigben/ |title=UK Parliament - Big Ben |access-date=2009-10-27}}</ref> the tower of [[Philadelphia City Hall]], the [[Rajabai Tower]] in [[Mumbai]], the [[Spasskaya Tower]] of the [[Moscow Kremlin]], the [[St Mark's Clocktower|Torre dell'Orologio]] in the [[Piazza San Marco]] in [[Venice]], [[Italy]], the [[Peace Tower]] of the [[Parliament of Canada]] in [[Ottawa]], and the [[Zytglogge]] clock tower in the [[Old City (Bern)|Old City]] of [[Bern]], [[Switzerland]].

==Records==
[[File:Birmingham MMB 31 University of Birmingham.jpg|thumb|right|upright=1.5|[[Joseph Chamberlain Memorial Clock Tower|Old Joe]] in Birmingham, England – the tallest freestanding clock tower in the world]]
The tallest freestanding clock tower in the world is the [[Joseph Chamberlain Memorial Clock Tower]] (Old Joe) at the [[University of Birmingham]] in [[Birmingham]], United Kingdom.<ref>{{cite web|url=http://www.skyscrapernews.com/buildings.php?id=156|title=Joseph Chamberlain Memorial Clock Tower|publisher=Skyscraper News|access-date=15 April 2014|archive-date=1 July 2018|archive-url=https://web.archive.org/web/20180701165056/http://www.skyscrapernews.com/buildings.php?id=156|url-status=dead}}</ref> The tower stands at {{convert|100|m|ft|abbr=off}} tall and was completed in 1908. The clock tower of [[Philadelphia City Hall]] was part of the tallest building in the world from 1894,<ref name=nps>[https://npgallery.nps.gov/GetAsset/b7e04e22-561d-42a0-95da-9cea7148d3a9/ "National Register of Historic Places Inventory - Nomination Form"]. ([https://web.archive.org/web/20171110114739/https://npgallery.nps.gov/GetAsset/b7e04e22-561d-42a0-95da-9cea7148d3a9/ archive]) National Park Service. page 10. Retrieved November 9, 2017. "The statue was … hoisted to the top of the tower in fourteen sections in 1894."</ref> when the tower was [[topped out]] and the building partially occupied,<ref name=occupy1>[https://web.archive.org/web/20100220000022/http://www.ajaxelectric.com/cityhall/history5.htm ""History of City Hall: 1886-1890"]. (archive) Retrieved November 9, 2017. "1889: Mayor Fitler moves into completed offices on west side."</ref><ref name=occupy2>[https://web.archive.org/web/20100220000029/http://www.ajaxelectric.com/cityhall/history6.htm "History of City Hall: 1891-1901"]. (archive) Retrieved November 9, 2017. "1891: State Supreme Court opens in permanent courtroom."</ref> until 1908.

Taller buildings have had clock faces added to their existing structure such as the [[Palace of Culture and Science]] in [[Warsaw]], with a clock added in 2000. The building has a roof height of {{convert|187.68|m|abbr=on}}, and an antenna height of {{convert|237|m|abbr=on}}. The [[NTT Docomo Yoyogi Building]] in [[Tokyo]], with a clock added in 2002, has a roof height of {{convert|240|m|ft|abbr=on}}, and an antenna height of {{convert|272|m|ft|abbr=on}}.

The [[Abraj Al Bait]], a hotel complex in [[Mecca]] constructed in 2012, has the largest and highest clock face on a building in the world, with its Makkah Royal Clock Tower having an occupied height of {{convert|494.4|m|ft|abbr=on}}, and a tip height of {{convert|601|m|ft|abbr=on}}.<ref>[http://www.skyscrapercenter.com/building/makkah-royal-clock-tower/84 "Makkah Royal Clock Tower "]. ''skyscrapercenter.com''. Council on Tall Buildings and Urban Habitat. Retrieved May 20, 2018.</ref> The tower has four clock faces, two of which are {{convert|43|m|ft|abbr=on}} in diameter, at about {{convert|400|m|ft|abbr=on}} high.<ref>[http://www.pct.ae/composite_projects.php?project=1 "Dokaae Tower Clock And Crescent"] {{Webarchive|url=https://web.archive.org/web/20120304173908/http://www.pct.ae/composite_projects.php?project=1 |date=2012-03-04 }}. ''pct.ae''. Premier Composite Technologies. Retrieved May 21, 2018.</ref>

==See also==
* [[List of clock towers]]
* [[Bell tower]]
* [[Minaret]]
* [[Street clock]]
* [[Thirteenth stroke of the clock]]

==References==
{{Reflist}}

== External links ==
{{Commons}}
* [http://www.towerclocks.org/ Towerclocks.org - Tower clocks database]
* [http://www.scotcities.com/railways/clocks.htm Railway Station Clock Towers] {{Webarchive|url=https://web.archive.org/web/20190222151926/http://www.scotcities.com/railways/clocks.htm |date=2019-02-22 }} Architecture of time

{{Authority control}}

{{DEFAULTSORT:Clock Tower}}
[[Category:Clock towers| ]]
[[Category:Hellenistic engineering]]
[[Category:Ancient inventions]]
[[Category:Clocks|Tower]]
[[Category:Ancient Greek technology]]
[[Category:Greek inventions]]