Editing Berlin Wall (section)

==Structure and adjacent areas==
===Layout and modifications===
{| class="wikitable float-right"
|+<ref>[http://www.chronik-der-mauer.de/index.php/de/Start/Detail/id/593791/page/0 Berliner Mauer (Stand 31. Juli 1989) Polizeipräsident von Berlin] {{Webarchive|url=https://web.archive.org/web/20210209114000/https://www.chronik-der-mauer.de/index.php/de/Start/Detail/id/593791/page/0 |date=9 February 2021 }}.</ref><ref>[http://www.chronik-der-mauer.de/index.php/de/Start/Detail/id/593791/page/0 Bundeszentrale für politische Bildung: ''Ministerium für Staatssicherheit der DDR''] {{Webarchive|url=https://web.archive.org/web/20210209114000/https://www.chronik-der-mauer.de/index.php/de/Start/Detail/id/593791/page/0 |date=9 February 2021 }}, siehe: ''Statistiken + "Grenzsicherung in Berlin"'' 1989.</ref>
! Length (km)
! Description
|-
|style="text-align:right" | 156.4{{0}}
| Bordering around West Berlin within 3.4&nbsp;m and 4.2&nbsp;m in height
|-
|style="text-align:right" | 111.9{{0}}
| Concrete walls
|-
|style="text-align:right" | 44.5{{0}}
| Metal mesh fence (along death strip)
|-
|style="text-align:right" | 112.7{{0}}
| Cross attachment in Potsdam
|-
|style="text-align:right" | 43.7{{0}}
| Cross attachment along the border of East and West Berlin
|-
|style="text-align:right" | 0.5{{0}}
| Remains of house fronts, land mansion bricks{{clarify|date=November 2019}}
|-
|style="text-align:right" | 58.95
| Wall-shaped front wall with a height of 3.40&nbsp;m
|-
|style="text-align:right" | 68.42
| Expanded metal fence with a height of 2.90&nbsp;m as a "front barrier"
|-
|style="text-align:right" | 161{{0}}{{0}}
| Light strip
|-
|style="text-align:right" | 113.85
| Limit signal and barrier fence (GSSZ)
|-
|style="text-align:right" | 127.5{{0}}
| Contact and signal fence
|-
|style="text-align:right" | 124.3{{0}}
| Border patrol
|-
! Actual number
! Descriptions
|-
|style="text-align:right" | 186
| Observation towers (302 in West-Berlin){{clarify|date=November 2019}}
|-
|style="text-align:right" | 31
| Implementing agencies
|-
|style="text-align:right" | 259
| Dog runs
|-
|style="text-align:right" | 20
| Bunkers
|}
[[File:Structure of Berlin Wall.svg|thumb|Structure of the Berlin Wall (left to right)<br/>
{{bulleted list|Border|Outer strip|Concrete wall with rounded top|Anti vehicle ditch|"Death strip" sand bank|Guard road|Lighting|Observation towers|Spikes or tank traps|Electrified fence with alarms|Inner wall|Restricted zone}}]]

The Berlin Wall was more than {{convert|140|km|mi}} long. In June 1962, a second, parallel fence, also known as a "hinterland" wall (inner wall),<ref>{{cite web |url=https://www.berlin.de/landesdenkmalamt/denkmale/berliner-mauer/mauer-denkmale/bornholmer-strasse-649637.en.php |title=Hinterland wall on Bornholmer Straße – Witness to the events of 9 November 1989 |publisher=Berlin.com |access-date=10 February 2020}}</ref> was built some {{cvt|100|m|yd}} farther into East German territory. The houses contained between the wall and fences were razed and the inhabitants relocated, thus establishing what later became known as the ''death strip''. The death strip was covered with raked sand or gravel, rendering footprints easy to notice, easing the detection of trespassers and also enabling officers to see which guards had neglected their task;<ref name="ineuropa"/> it offered no cover; and, most importantly, it offered clear fields of fire for the Wall guards.

Through the years, the Berlin Wall evolved through four versions:<ref name="thoughtco.com">{{cite web |url=https://www.thoughtco.com/the-berlin-wall-28-year-history-1779495 |title=All About the 28-Year History, Rise and Fall of the Berlin Wall |first1=Jennifer Rosenberg Jennifer Rosenberg is a |last1=historian |first2=History |last2=Fact-Checker |first3=Freelance Writer Who Writes About 20th-Century History |last3=Topics |website=ThoughtCo |access-date=15 February 2018 |archive-date=16 February 2018 |archive-url=https://web.archive.org/web/20180216030017/https://www.thoughtco.com/the-berlin-wall-28-year-history-1779495 |url-status=live }}</ref>
*Wire fence and concrete block wall (1961)
*Improved wire fence (1962–1965)
*Improved concrete wall (1965–1975)
*{{lang|de|Grenzmauer 75}} (Border Wall 75) (1975–1989)

The "fourth-generation Wall", known officially as "{{lang|de|Stützwandelement UL 12.11}}" (retaining wall element UL 12.11), was the final and most sophisticated version of the Wall. Begun in 1975<ref>{{cite web |first=Heiko |last=Burkhardt |url=http://www.dailysoft.com/berlinwall/history/facts.htm |title=Facts of Berlin Wall – History of Berlin Wall |publisher=Dailysoft.com |access-date=9 November 2009 |archive-date=11 March 2021 |archive-url=https://web.archive.org/web/20210311194422/https://www.dailysoft.com/berlinwall/history/facts.htm |url-status=live }}</ref> and completed about 1980,<ref name = "cgqmzv">{{cite web |author1=P. Dousset |author2=A. Souquet |author3=S. Lelarge |url=http://www.wall-berlin.org/gb/mur.htm |title=Berlin Wall |access-date=9 November 2009 |archive-url=https://web.archive.org/web/20060913215115/http://www.wall-berlin.org/gb/mur.htm |archive-date=13 September 2006}}</ref> it was constructed from 45,000 separate sections of reinforced concrete, each {{convert|3.6|m|ft}} high and {{cvt|1.2|m|ft}} wide, and cost [[East German mark|DDM]]16,155,000 or about US$3,638,000.<ref>{{cite web |author=Heiko Burkhardt |url=http://www.dailysoft.com/berlinwall/history/facts_02.htm |title=Fourth Generation of Berlin Wall – History of Berlin Wall |publisher=Dailysoft.com |access-date=9 November 2009 |archive-date=11 February 2021 |archive-url=https://web.archive.org/web/20210211080754/https://www.dailysoft.com/berlinwall/history/facts_02.htm |url-status=live }}</ref> The concrete provisions added to this version of the Wall were done to prevent escapees from driving their cars through the barricades.<ref name="Berlin Wall 2009">''Rise and Fall of the Berlin Wall''. [[History (American TV channel)|History Channel]], 2009. DVD-ROM.</ref> At strategic points, the Wall was constructed to a somewhat weaker standard, so that East German and Soviet armored vehicles could easily break through in the event of war.<ref name="Berlin Wall 2009"/>

[[File:Exterior of East Berlin Neue Zeit newspaper, with Berlin Wall in foreground.jpg|thumb|Smooth piping lined the top of the Wall, intended to make it more difficult to scale. The areas just outside the wall, including the sidewalk, are ''de jure'' East Berlin territory (1984).]]
[[File:Berlin Wall death strip, 1977.jpg|thumb|This section of the Wall's "death strip" featured [[Czech hedgehog]]s, a [[guard tower]] and a cleared area, 1977.]]
The top of the wall was lined with a smooth pipe, intended to make it more difficult to scale. The Wall was reinforced by mesh [[fence|fencing]], signal fencing, anti-vehicle trenches, [[barbed wire]], dogs on long lines, "[[bed of nails|beds of nails]]" (also known as "Stalin's Carpet") under balconies hanging over the "death strip", over 116 [[watchtower]]s,<ref>{{cite web |author=Popiolek |url=http://www.die-berliner-mauer.de/en/fakten.html |archive-url=https://web.archive.org/web/20071012011801/http://die-berliner-mauer.de/en/fakten.html |archive-date=12 October 2007 |title=The Berlin Wall : History of Berlin Wall : Facts |publisher=Die-berliner-mauer.de |access-date=9 November 2009 |url-status=dead}}</ref> and 20 [[bunker]]s with hundreds of guards. This version of the Wall is the one most commonly seen in photographs, and [[List of Berlin Wall segments|surviving fragments]] of the Wall in Berlin and elsewhere around the world are generally pieces of the fourth-generation Wall. The layout came to resemble the [[inner German border]] in most technical aspects, except that the Berlin Wall had no landmines nor [[spring-gun]]s.<ref name="ineuropa">According to Hagen Koch, former [[Stasi]]-officer, in [[Geert Mak]]'s documentary [[In Europa (TV program)]], episode [http://www.ineuropa.nl/programmas/36788896/afleveringen/40824233/ ''1961 – DDR''] {{Webarchive|url=https://web.archive.org/web/20210209113951/http://v.youku.com/v_show/id_XNTEzNDkyMDY4.html |date=9 February 2021 }}, 25 January 2009</ref> Maintenance was performed on the outside of the wall by personnel who accessed the area outside it either via ladders or via hidden doors within the wall.<ref>{{cite book |url=https://books.google.com/books?id=QbfvCwAAQBAJ&q=berlin+wall+outside+maintenance&pg=PT61 |title=The Berlin Wall and the Intra-German Border 1961–89 |first=Gordon L. |last=Rottman |date=2012 |publisher=Bloomsbury Publishing |via=Google Books |isbn=9781782005087}}</ref> These doors could not be opened by a single person, needing two separate keys in two separate keyholes to unlock.<ref>{{cite web |url=https://www.youtube.com/watch?time_continue=275&v=OwQsTzGkbiY |title=Walled in! – The inner German border |last=DW News English |date=30 June 2009 |via=YouTube |access-date=13 November 2017 |archive-date=4 November 2020 |archive-url=https://web.archive.org/web/20201104212348/https://www.youtube.com/watch?time_continue=275&v=OwQsTzGkbiY |url-status=live }}</ref>

As was the case with the inner German border, an unfortified strip of Eastern territory was left outside the wall.<ref name="auto">{{cite book |url=https://books.google.com/books?id=QbfvCwAAQBAJ&q=berlin+wall+outside+maintenance&pg=PT61 |title=The Berlin Wall and the Intra-German Border 1961–89 |first=Gordon L. |last=Rottman |date=2012 |publisher=Bloomsbury Publishing |via=Google Books |isbn=9781782005087}}</ref> This outer strip was used by workers to paint over graffiti and perform other maintenance on the outside of the wall<ref name="auto"/> Unlike the inner German border, however, the outer strip was usually no more than four meters wide, and, in photos from the era, the exact location of the actual border in many places appears not even to have been marked. Also in contrast with the inner German border, little interest was shown by East German law enforcement in keeping outsiders off the outer strip; sidewalks of West Berlin streets even ran inside it.<ref name="auto"/>

Despite the East German government's general policy of benign neglect, vandals were known to have been pursued in the outer strip, and even arrested. In 1986, defector and political activist Wolfram Hasch and four other defectors were standing inside the outer strip defacing the wall when East German personnel emerged from one of the hidden doors to apprehend them. All but Hasch escaped back into the western sector. Hasch himself was arrested, dragged through the door into the death strip, and later convicted of illegally crossing the ''[[de jure]]'' border outside the wall.<ref>{{cite web |url=https://www.upi.com/Archives/1987/01/09/Foreign-News-Briefs/9799537166800/ |title=Foreign News Briefs |website=UPI |access-date=14 November 2017 |archive-date=14 November 2017 |archive-url=https://web.archive.org/web/20171114093350/https://www.upi.com/Archives/1987/01/09/Foreign-News-Briefs/9799537166800/ |url-status=live }}</ref> Graffiti artist [[Thierry Noir]] has reported having often been pursued there by East German soldiers.<ref>{{cite news |access-date=31 October 2018 |title=Graffiti in the death strip: the Berlin wall's first street artist tells his story |url=https://www.theguardian.com/artanddesign/gallery/2014/apr/03/thierry-noir-graffiti-berlin-wall |newspaper=The Guardian |date=3 April 2014 |issn=0261-3077 |via=www.theguardian.com |archive-date=1 December 2017 |archive-url=https://web.archive.org/web/20171201142426/https://www.theguardian.com/artanddesign/gallery/2014/apr/03/thierry-noir-graffiti-berlin-wall |url-status=live }}</ref> While some graffiti artists were chased off the outer strip, others, such as [[Keith Haring]], were seemingly tolerated.<ref>{{cite web |first1=Philip |last1=Oltermann |access-date=31 October 2018 |title=A line in history: the east German punks behind the Berlin Wall's most radical art stunt |url=https://www.theguardian.com/artanddesign/2014/nov/03/east-german-punks-berlin-wall-radical-art-stunt |date=3 November 2014 |website=The Guardian |archive-date=24 September 2018 |archive-url=https://web.archive.org/web/20180924114802/https://www.theguardian.com/artanddesign/2014/nov/03/east-german-punks-berlin-wall-radical-art-stunt |url-status=live }}</ref>

===Surrounding municipalities===
Besides the sector-sector boundary within Berlin itself, the Wall also separated West Berlin from the present-day state of [[Brandenburg]]. The following present-day municipalities, listed in counter-clockwise direction, share a border with the former West Berlin:
*[[Oberhavel]]: [[Mühlenbecker Land]] <small>(partially)</small>, [[Glienicke/Nordbahn]], [[Hohen Neuendorf]], [[Hennigsdorf]]
*[[Havelland (district)|Havelland]]: [[Schönwalde-Glien]], [[Falkensee]], [[Dallgow-Döberitz]]
*[[Potsdam]] (urban district)
*[[Potsdam-Mittelmark]]: [[Stahnsdorf]], [[Kleinmachnow]], [[Teltow]]
*[[Teltow-Fläming]]: [[Großbeeren]], [[Blankenfelde-Mahlow]]
*[[Dahme-Spreewald]]: [[Schönefeld]] <small>(partially)</small>