When John Lennon was murdered in 1980 he became a hero to some and his picture was painted on this wall.
The threat of prison couldn’t keep people from slipping there at night to scrawl graffiti first in the form of Beatles lyrics and odes to Lennon, then they came to paint their own feelings on the wall. The Communist police tried repeatedly to whitewash over the portrait and messages, but they could never manage to keep the wall clean. It used to be covered in anti-Communist graffiti, now it is covered in messages of love and peace. The original portrait of Lennon is long lost under the layers of new paints but if you look hard enough you can still find tributes to Lennon and a yellow submarine!
The wall, at Velkoprevorske Namesti, Mala Strana, is owned by the Knights of the Maltese Cross, who allow the graffiti to continue.