Poor Berlin. After all the destruction the Nazi's brought upon their city, the Berliners had more to come. The Berlin wall was not originally stone, but merely barbed wire rolled out without warning in the middle of the night, with soldiers posted all along. People woke up to go to work or school or return home to family members and found that they were now permanently separated. Loved ones ripped from your arms while you were sleeping, and you had no idea until the next day.
Now on the east side of the wall you couldn't get near it. There were guards with orders to shoot on site, and plenty of other traps and smaller walls. But on the western side, the sad and angry people painted messages they had to hope that one day their loved ones on the other side might get to see.