Considering on the crisis and dilemma of monumentality in Modern architecture, this study analyse the historic reason of decay and new possibility of monumentality within the context of contemporary socio-cultural context. Historically monumentality has been considered as a main substance of High architecture in e tradition of Western Architecture. Difference between building and architecture mainly lies in monumentality which brings about esthetic quality. Usually architects take it granted that the physical and formal characteristics automatically cause the monumentality, But since the modem period the decline of communicative and representative function of architecture made this belief questionable. As Monumentality itself faced the dilemma with the modernity, ironically architects has to response to the task to handle the increasing social demands of monumental building. This study firstly shows the dilemma of monumentality in depth in case of the holocaust museum. Then we analyse the concept of monumentality itself by means of theoretical view of A. Loos and A Riegl We also analyse the change of role which monumental building played in history. Cultural and social change of context, and fundamental change of architecture old way of building a monument impossible. In conclusion this study proposes the new concept and searches new horizon of monumentality with a finding of the otherness of monumentality. Conventional monumental building language has to give way to new approaches. With some examples we already can find a new possibility.