This thesis assembles monuments of contemporary art, which are partially or completely invisible. These monuments, which were mainly built in Germany since the 1980s, reduce the classic monuments which were based on monumentality to absurdity. As counter-monuments they mostly address a negative memory. The traditional form of remembrance, which was mainly linked to the glorification of person and nation since the 19th Century, became impossible after the Nazi regime, with its war and the Holocaust. After the political climate had changed in the 1970s, a need for accounting for the past and public discussions gradually developed in the German past. This thesis addresses the question, whether the hidden monuments, other than visualising the repression and oblivion (through invisibility), also reach their goal ? remembrance and accounting for the past.This paper outlines the traditional concept of the monument, and the first invisible works from the sector of commemoration of the dead, as well as first underground concepts. Subsequently the counter-monuments designed for fascism, Holocaust and war in Germany are presented in chronological order, as well as their intention and effect. Finally two monuments, which work with invisibility, not in the sense of a memorial, but by creating a zone of mental freedom, are discussed. Works of the following artists are presented in detail in the paper: Christian Boltanski, Mark Brest van Kampen, Walter De Maria, Jochen Gerz, Rudolf Herz, Horst Hoheisel, Margrit Kahl, Andreas Knitz, Reinhard Matz, Claes Oldenburg, Pablo Picasso, Esther Shalev-Gerz, Gerd Stange, Micha Ullman, Timm Ulrichs.The analysis of the individual monuments illustrates, that all named works have provoked intensive processes in the population and that the participatory approach as such was essential: the artists have reached their intention to trigger a debate and encourage the people of their time to reflect on the past events.