An empire is a large political unit that typically consists of various territories and peoples under a single sovereign authority. Empires often expand through conquest, colonization, or diplomacy, allowing them to control vast regions and diverse cultures. Historical examples include the Roman Empire and the British Empire, which both had significant influence on global politics and culture. Empires are characterized by their centralized governance, where a dominant power exercises control over its subjects. They can impact trade, language, and social structures within their territories. The rise and fall of empires often shape the course of history, leading to changes in borders and the emergence of new nations.