3 days ago · Moscow, city, capital of Russia since the late 13th century. It is not only the political center of Russia but also the country’s most populous city and its industrial, cultural, scientific, and …

Overview of key battles during the American Revolution, highlighting pivotal moments and their impact on the course of history.

5 days ago · ideology, a form of social or political philosophy in which practical elements are as prominent as theoretical ones. It is a system of ideas that aspires both to explain the world and to …

Jan 27, 2026 · PDA, an electronic handheld organizer used in the 1990s and 2000s to store contact information, manage calendars, communicate by e-mail, and handle documents and spreadsheets, …

Biosphere, relatively thin life-supporting stratum of Earth’s surface, extending from a few kilometers into the atmosphere to the ocean’s deep-sea vents. This global ecosystem continuously cycles matter. It …

Jan 22, 2026 · Murder is the legally unjustified killing of one person by another.

Feb 5, 2026 · A helicopter is an aircraft with at least one horizontal propeller or rotor which enables the craft to take off and land vertically, move in any direction, and remain stationary in the air. An …

Jan 8, 2026 · Aviation, the development and operation of heavier-than-air aircraft. The term military aviation refers to the development and use of military aircraft, while the term civil aviation refers to all …

Feb 6, 2026 · Industrial Revolution - Technology, Factories, Change: How the Industrial Revolution expanded throughout Europe

Jan 11, 2026 · Epiphany is a Christian holiday commemorating the first manifestation of Jesus Christ to the Gentiles, represented by the Magi, and the manifestation of his divinity, as it occurred at his …