The Inner-German Border (IGB) saw large numbers cross between 1946 and 1952, somewhere around 600,000, as it became increasingly obvious that there would be no unification between the Western occupied zones and Soviet occupied zone. In 1952, the new DDR government began to build a full fenced barrier between the two Germanys, guarded by 50,000 members of the Grenztruppen der DDR. A 10m plowed strip behind the primary fence would show footprints of any otherwise undetected escape. This was backed by another fence and a 500m buffer zone. Watchtowers and bunkers were placed at intervals. The strip between fences often had anti-personnel mines placed. Eventually the fence was mined (3 tripwire mines on each pole, low, middle, and high), and the buried mines removed. In some areas they constructed a wall, with free-rotating pipes on the top to prevent anyone getting a grip on the top. Anti-vehicle obstacles were also used in many places.

A road for patrols ran behind this. Guards were constantly rotated so they never knew who they would be paired with. Only people with special permits were allowed within 5km of the border, and several thousand were relocated farther from the border.

Uogrades to the system were pretty constant. The watchtowers had searchlights, and eventually night vision devices. Other detection systems were installed.

Despite all this, there were successful attempts to escape, including a daring one involving a balloon in 1979.

White markers delineated the actual border, and the fence could be a considerable distance behind it. On the west side, the area was marked with a 50m restricted zone to prevent accidental violations of the border, and a 1km zone where only authorized personnel could enter (This did not apply to West Germans, some of whom lived within this zone). For the US sector, the border was monitored by Armored Cavalry troops who patrolled the border.

US ARMY BORDER OPERATIONS IN GERMANY, 1945-1983, William E. Stacy