Editing Inner German border (section)

===1967–89: the "Modern Frontier"===
[[File:BGS-Hubschrauber Alouette II.jpg|thumb|250px|alt=Green-painted helicopter with "Bundesgrenzschutz" on the side flies parallel to a border fence with a gate in it, behind which are two East German soldiers and a canvas-sided truck.|A ''Bundesgrenzschutz'' [[Alouette II]] helicopter patrols the West German side of the inner German border, 1985.]]
The GDR decided to upgrade the fortifications in the late 1960s to establish a "modern frontier" that would be far more difficult to cross. Barbed-wire fences were replaced with harder-to-climb [[expanded metal]] barriers; directional anti-personnel mines and anti-vehicle ditches blocked the movement of people and vehicles; tripwires and electric signals helped guards to detect escapees; all-weather patrol roads enabled rapid access to any point along the border; and wooden guard towers were replaced with prefabricated concrete towers and observation bunkers.<ref name="Rottman-20"/>

Construction of the new border system started in September 1967.<ref name="Stacy-185">[[#Stacy|Stacy (1984)]], p. 185.</ref> Nearly {{convert|1300|km|0}} of new fencing was built, usually further back from the geographical line than the old barbed-wire fences.<ref name="Rottman-20" /> The upgrade programme continued well into the 1980s.<ref>[[#Stacy|Stacy (1984)]], p. 189.</ref> The new system immediately reduced the number of successful escapes from around 1,000&nbsp;people a year in the mid-1960s to only about 120 per year a decade later.<ref name="Mulligan">[[#Mulligan|Mulligan (1976-10-28)]].</ref>

The introduction of West German Chancellor [[Willy Brandt]]'s ''[[Ostpolitik]]'' ("Eastern Policy") at the end of the 1960s reduced tensions between the two German states. It led to a series of treaties and agreements in the early 1970s, most significantly a treaty in which East and West Germany recognised each other's sovereignty and supported each other's applications for UN membership, although neither state changed its view on the citizenship issue.<ref>Official presentation of the text of the treaty as given by the United States - Department of State - ''Documents on Germany 1944-1985'' ( Washington: Department of State, [s.d], pp. 1215-1217 ), reproduced  here: [http://www.ena.lu/basic-treaty-21-december-1972-020302440.html]</ref>&nbsp; Reunification remained a theoretical objective for West Germany, but in practice that objective was put aside by the West and abandoned entirely by the East.<ref>[[#Stacy|Stacy (1984)]], p. 176.</ref> New crossing points were established and East German crossing regulations were slightly relaxed, although the fortifications were as rigorously maintained as ever.<ref name="Jarausch-17"/>

In 1988, the GDR leadership considered proposals to replace the expensive and intrusive fortifications with a high-technology system codenamed ''Grenze 2000''. Drawing on technology used by the [[Red Army|Soviet army]] during the [[Soviet-Afghan War|Soviet–Afghan War]], it would have replaced the fences with sensors and detectors. However, the plan was never implemented.<ref>[[#MullerEnbergs|Müller-Enbergs (1988)]], p. 437.</ref><ref>[[#Koop|Koop (1996)]], p.</ref>