How large was the Roman Empire?

How large was the Roman Empire?

At its fullest extend, in the 2nd century CE, it stretched 4,000 km (2,500 miles) from Spain in the west to the Caspian Sea in the east, and from Britain in the north to Egypt in the south. Of course, this didn't happen overnight-in fact, it took more than 700 years for Rome to grow from a small village to a superpower.