Revolution 

Social and political revolutions can both be characterised by violence, and the vast changes in power structures that result can often result in further, institutionalised, violence, as in the Russian and French revolutions (with the "Purges" and "the Terror", respectively). A political revolution is the forcible replacement of one set of rulers with another (as happened in France and Russia), while a social revolution is the fundamental change in the social structure of a society; many would point to the Spanish Revolution, which occurred parallel to the Spanish Civil War, as an example of this.

Some political philosophers regard revolutions as the means of achieving their goals. Most anarchists advocate social revolution as the means of breaking down the structures of government and replacing them with nonhierarchal institutions, while Marxist communists take revolution to be one strategy, possibly accompanied by the use of electoral politics to take over, rather than overthrow, the institution of government, their aim being to create a communist society.

A revolution is normally considered to be a relatively swift change: for example, in Spain, in 1936, anarchist and communist groups quickly took control of many areas on the first day of the Civil War (triggered by Franco's attempted coup). However, most of the philosophers mentioned above regard these first acts and processes as merely the opening of a revolution. In The Conquest of Bread, the "Anarchist Prince" Peter Kropotkin writes that

[w]e have all been bent on studying the dramatic side of revolutions so much, and the practical work of revolutions so little, that we are apt only to see the stage effects, so to speak... the fight of the first days.... But this fight... is soon ended, and it is only after the breakdown of the old system that the real work of revolution can be said to begin.[2] (http://dwardmac.pitzer.edu/Anarchist_Archives/kropotkin/conquest/ch2.html)

There can also be "institutionalized revolutions" in which the ideas, slogans, and personalities of the revolution continue to play a prominant role in a country's political culture[?], long after the revolution's end. As mentioned, Communist nations regularly institutionalize their revolutions to legitimize the actions of their governments. Some non-communist nations, like the United States, France, or Mexico also have institutionalized revolutions, and continue to celebrate the memory of their revolutionary past through holidays, artwork, songs, and other venues.