 Complete the following phrase:  Many have cited the influence of the series of revolutions in Central and Eastern Europe in the late 1980s and early 1990s, particularly the Velvet Revolution in Czechoslovakia in 1989. The police attacked a peaceful demonstration by students mostly from Charles University  and, in time, contributed to the collapse of the communist government in Czechoslovakia. However, the roots of the pacifist floral imagery may go even further back to the non-violent 