Khrushchev and East German leader, Walter Ulbricht ordered the closure of the border between East and West Berlin.
East German police and soldiers sealed the most frequently-used border crossings with barbed wire.
Soviet troops began to replace the wire with a concrete wall, which eventually stretched over a hundred miles.
It not only ran through the centre of Berlin, but also wrapped around West Berlin, cutting it off from East Germany - some sections of the wall were three metres high.
The Berlin Wall became heavily fortified with watch-towers, anti-tank devices, ditches, barbed wire, guard dogs, powerful searchlights and minefields to prevent escapes.
Buildings overlooking the Wall were demolished or had their windows bricked up so that people could not jump from them.