During the Communist regime in Prague, which lasted fom February 1948 till November 1989 when the Velvet Revolution took place, listnening to Western music was a risky business. Records of bands like Beatles and Rolling Stones were not sold in stores, so people were smuggling them from the closest contries of the Western Block. Listening to songs about liberty and love provided an escape for people who lived under the Socialist rule.
John Lennon, as a musician and as a Human Rights activist, was especially popular among the Communist opposition. His appeal to "make love not war" resonated with the Czech population and created a huge fan base. After John Lennon's death on the 8th of December 1980, a young Czech artist made a graffiti dedicated to John Lennon on this wall. More people supported this initiative and the plain white wall turned rainbow with quotes of John Lennon's songs and wishes for world peace. Since then Lennon Wall became one of the centres of political protests against the communist regime and its oppression of freedom of speech.
Nowadays, Lennon Wall is visited by thousands of tourists who leave their messages there. It even inspired the creation of another John Lennon Wall in Hongkong after its streets were taken by protests in summer 2019.