system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If the Berlin wall was built to separate East Germans from West Germans, why was it only built across Berlin?

Trying to research the history behind the Berlin Wall but i don’t understand why the wall only separated Berlin. Wouldn’t it make more sense if the whole of East and West Germany were separated by a wall?
gpt
West Berlin Was surrounded by the DDR (or east Germany) which made it a high risk location when it comes to illegal border crossings (many people, they can come from all sides, pretty much no distance between the two states). Therefore they decided to build a wall in order to control it more efficiently.

However, the large border between east and west wasn't uncontrolled either. There were many border guards and posts on the roads while the rest was mainly secured by fences, towers and even self-firing systems as well as anti-personnel mines. 

Escaping over the border was a very risky and often deadly project no matter where.