The Berlin Wall was a not only a symbol of partition, it was a constant reminder that war was a real threat in Europe.

Europe was a divided continent at the end of World War II as the former allies who defeated Nazi Germany argued over how to rebuild a peaceful world.

Germany was spilt into four zones occupied by USA, France, UK and USSR. Berlin, which in was in the USSR controlled zone, was also divided into four but the three western countries soon amalgamated their sections.

Political differences between the superpowers led to the Stalin-led USSR imposing a blockade of the city in an effort to force the western powers out.

It was the beginning of the Cold War, and decades of tension and divide in Europe.

The founding of two separate German states increased the tension as West Berlin – then operating as a free city - was surrounded by East German territory.

Berlin became a magnet for East Germans wanting to flee to the west and an estimated 3.5 million citizens escaped over the border.

In 1961 the USSR decided to end the mass defections and literally cement Berlin’s separation by building a concrete barrier.

Work on the wall began in the dark of night on August 13, 1961 and the following morning Berliners woke to find themselves in a divided city, cut off from family and friends.

East German troops continued to work on the concrete structure over the following days and weeks until it stretched the length of the entire city.

Barbed wire fences were put in place and East German border guards issued with shoot-to-kill orders for anybody trying to cross over to the west.

The following year a second wall was built to stop Berliners trapped in the east from escaping to reunite with families in the west.

However, breaches of the barrier continued and in 1965 a new wall consisting of concrete slabs placed between steel girders and concrete posts was built.

Over 100 watchtowers were built to keep an eye on the wall and over the years it was reinforced by mesh fencing, anti-vehicle trenches and barbed wire.

Despite the dangers, it’s believed around 5,000 people managed to get through the heavily guarded Berlin border but over 130 died trying to escape.