The “wall” literally went up overnight on a weekend. People went to bed in one city and woke up in either East or West Berlin. It was later beefed up and filled in, but the “state border” was closed to travel on the night of 12/13 August, 1961. Tales of people who were trapped on the wrong side of the wall are some of the most heartbreaking I’ve come across. Peter Wyden’s book “Wall” and Anna Funder’s book “Stasiland” interview people who were in that situation and do a pretty good job of expressing how horrifying it was and why people risked their lives to get back across to the West.
The Berlin Wall entirely surrounded West Berlin, so no you couldn’t “simply go around it”.The wall started being built in late 1961, but throughout the years it went through many changes. Wikipedia states there were four main versions of the wall: 1. Wire fence (1961) 2. Improved wire fence (1962–1965) 3. Concrete wall (1965–1975) 4. Grenzmauer 75 (Border Wall 75) (1975–1989)
(There is an intact part of the Wall on Bernauerstrasse with a large open air museum. They go through it all step by step explaining everything: people jumping out of windows, windows being bricked up, then people tunneling under, children stuck on one side, trip wires attached to machine guns, dogs patrolling on wires….its just so crazy.)