The Roman Empire was one of the largest and most influential empires in history. At its peak, it covered an area of approximately 5 million square kilometers (1.9 million square miles), encompassing territories across Europe, North Africa, and the Middle East. This vast expanse included modern-day Italy, Spain, France, the United Kingdom, Greece, Turkey, and Egypt, among others. Its population is estimated to have been between 50 and 90 million people, or about 15-20% of the world’s population at the time.