The wall went up on August 13th 1961. However, it was only a barbed wire
fence at first.
Between August 1961 and the end of the year the wall was extended considerably.
The first stage was the building of a concrete wall. Then space was cleared
either side of the wall. The spaces were patrolled by armed guards and dogs.
There were also towers with searchlights.
This document comes from a Foreign Office report which was passing on information
provided by military observers at the wall.
The Brandenburg Gate was in the very heart of Berlin, near the crossing
point known as Checkpoint Charlie.