Topic: Tell me a short, interesting fact about

The Roman Empire reached its largest known extent during the reign of Emperor Trajan, who ruled from 98 to 117 AD. At its peak, the empire encompassed 6.5 million square kilometers (2.5 million square miles), which is larger than the combined land areas of the modern-day United States, China, and India. The Roman Empire was the largest empire in the world for several centuries and was known for its advancements in law, politics, economy, engineering, architecture, art, and literature.