Why was the Berlin Wall built?

The Berlin Wall was built to divide East and West Germany. Since at that time, before the construction of the wall, many residents moved from the east to the west, where salaries were significantly higher, this was one of the reasons. But the main reason is the aggravation between NATO and the Warsaw Pact countries, which led to the construction of the wall, which lasted until 1989. It was also called the “Shameful Wall”, and it stretches for 155 kilometers along the border between two separate parts of Germany.