Imperialism is a policy or ideology where a country extends its power and influence over other nations or territories, often through military force, colonization, or economic dominance. This practice has shaped global relations and led to significant cultural, political, and economic changes in the affected regions, such as Africa and Asia. Historically, imperialism has been driven by the desire for resources, strategic advantages, and the spread of cultural values. Notable examples include the British Empire and the Roman Empire, which expanded their territories and exerted control over vast areas, leaving lasting legacies that continue to impact the world today.