revolution

thumb|Eugène Delacroix's romantic painting, La liberté guidant le peuple – "Liberty Guiding the People". An example of a revolution in the political sense thereof. In political science, a revolution (, 'a turn around') is a rapid, fundamental transformation of a society's class, state, ethnic or religious structures. According to sociologist Jack Goldstone, all revolutions contain "a common set of elements at their core: (a) efforts to change the political regime that draw on a competing vision (or visions) of a just order, (b) a notable degree of informal or formal mass mobilization, and (c) efforts to force change through noninstitutionalized actions such as mass demonstrations, protests, strikes, or violence."

Revolutions have occurred throughout human history and varied in their methods, durations and outcomes. Some revolutions started with peasant uprisings or guerrilla warfare on the periphery of a country; others started with urban insurrection aimed at seizing the country's capital city. Revolutions can be inspired by the rising popularity of certain political ideologies, moral principles, or models of governance such as nationalism, republicanism, egalitarianism, self-determination, human rights, democracy, liberalism, fascism, or socialism. A regime may become vulnerable to revolution due to a recent military defeat, or economic chaos, or an affront to national pride and identity, or persistent repression and corruption. Revolutions typically trigger counter-revolutions which seek to halt revolutionary momentum, or to reverse the course of an ongoing revolutionary transformation.