In a country that has been characterized by its high level of violence and historically strong repression of social movements and mobilizations, people demonstrated peacefully during twenty weeks in Guatemala City 2015. The mobilizations started after the revelation of a corruption network described as The Line, which involved both the Guatemalan Government and the Guatemalan Superintendence of Tax Administration. Each Saturday from April – August, Guatemalans gathered at the main square in the Capital City, to protest against corruption and to demand the resignation of President Otto Pérez Molina and Vice President Roxana Baldetti. After intensive demonstrations calling for the Vice-Presidents resignation, Baldetti resigned on May 8. The President resigned on September 2, four days before the general elections and both Baldetti and Pérez Molina were sentenced to prison because of their involvement in the corruption network. This essay aims to give answer to why people mobilized during several weeks and to create a greater understanding for why the mobilizations occurred. The Political Process Model has been used to analyze the character of the protests. This qualitative study is based on 16 semi-structured interviews conducted in Guatemala during the period of October – December 2015. A targeted selection and a snowball sampling method were used to identify persons to interview. The research showed that people identified the situation in Guatemala as a political crisis, which encouraged a broad participation in the protests. The traditional dynamic of challengers and members changed during the weeks of demonstrations. Since traditional polity members turned into challengers, the mobilizations had a high political leverage which made state led repression less likely. Therefore the demonstrations were interpreted as safe and consequently the participation increased. Traditional movements put their specific demands aside in order to be part of the collective demands against corruption. In other words, persons participated rather as individuals than as representatives from their movements.