German reunification
After West Germany's economy began to grow faster and faster in the 1950s, while East Germany's economy was not doing so well, many people moved from East to West Germany. To stop this emigration, the border between East and West Germany was closed in 1961 by East German forces. This border was part of the Iron Curtain. Between 1961 and 1989, leaving East Germany was very hard and extremely dangerous.  Officially leaving East Germany took years to be approved, and people who applied were often spied on by East German police.  Many people who tried to flee over the border were shot and killed there.