Shortly after the death of John Lennon, this stone wall surrounding the Maltese Gardens was transformed into an impromptu memorial with a painting of the singer’s face. Lighted candles accompanied quotes from John’s songs about world peace and freedom, and soon slogans criticizing the totalitarian regime began to appear. With the arrival of democracy, the wall has lost some of its significance, but it still remains as a colourful display of messages and tags.
Source: https://www.prague.eu/en/object/places/128/john-lennon-wall-zed-johna-lennona