Collective memory is a therm which individuals and society encounter all the time in everyday life, even if we are not aware. We are talking about collectively learned and accustomed things, which are changed relatively fast and in perspectives of different individuals take differenet point of view. Collective memory is inherent with collective memory of indiviudal. This two types of memory constantly intertwine with each other. Collective memory can not exist without individual memory and vice versa. In process of creating of individual memory, there are many factors, such as time, space, historical moment etc. There are also differences between adult memory and childhood memory. Individual always expirience his memory based on group in which he operates, because that group »teach« individual how to reminisce things in correct way. Individual place himself in groups based on identities. Beacause of this, different groups can have different collective memory for the same events. Collective memory affect in formation of larger groups, such as nation. Nation collectively take certain characteristics and traditions and based on these, establish itself as entity. Based on collective memory, individuals and groups define its past and also make decisions for the future. In second part of this work, analysis reflects theory on case of Algerian civil war and on consequences of this civil war.