The Roman Civilization developed along the Tiber River in Italy, beginning as villages that united in the 8th century BC to form the city of Rome. Rome transitioned from a kingdom ruled by elected kings, to a republic led by officials like Julius Caesar, to a vast empire under emperors like Augustus. At its height, Rome was the largest city in the world, with citizens divided into classes and slaves. The Romans built temples, amphitheaters like the Colosseum, and advanced infrastructure, while Latin was the official language and togas displayed social status.