What was the biggest empire in history?

What was the biggest empire in history? The answer, writes Benjamin Plackett in Live Science, depends on whether you think in terms of fraction of living humans or number of living humans, revealing the challenges inherent in attempting to compare time periods:

That’s without getting into the pros and cons of the other ways to measure size: largest land mass; largest contiguous land mass; largest army; largest gross domestic product; and so on.

But one alternative would be counted in years: we should measure empires by their long-term influence and stability, according to Martin Bommas, Director of the Macquarie University History Museum in Sydney:

“I think that to be classed as an empire, you need to have a period of peace to bring prosperity,” Bommas added. “If you look at it through years lasted, the Romans won this competition hands down.”