Political systems are shaped not only by formal institutions but also by a variety of actors and processes that operate within, and sometimes against, the state. Social movements, which are collective challenges by people with common purposes in sustained interaction with elites and authorities, are a key process of political change. A distinction is often made between traditional social movements, which were frequently class-based and focused on economic justice, such as labour movements, and new social movements that have emerged since the 1960s. These new social movements are typically concerned with post-materialist issues such as environmentalism, feminism, and human rights, focusing more on identity, lifestyle, and culture. Operating in a similar space are Non-Governmental Organisations and civil society campaigns. NGOs are typically formal, professionalized organizations that advocate for specific causes or provide services, often working to influence policy through lobbying, research, and public awareness campaigns. Civil society campaigns are broader efforts that may involve a coalition of NGOs, social movements, and individual citizens. At the most extreme end of the spectrum of political processes is revolution. Unlike social movements or campaigns that seek to influence or reform the system, a revolution involves a fundamental and often rapid transformation of a state's political institutions and social structures, frequently accompanied by class upheaval and violence.