It is the wall of freedom of expression although the truth that has become a tourist where people put their name or any other nonsense that has nothing to do with the purpose of the wall, is overcrowded. The important thing about the wall is that it was a place where at the time of repression in Prague they started to put songs by John Lennon with lyrics that incited freedom and that was not well seen, then they continued to post messages until it began to mass and put anything. Tourism is fine as long as you respect the monuments and cities that you visit.