I am always fascinated by this question: what was the biggest empire in the entire history of the world? The answer is more interesting than it seems.

The British Empire takes the top spot with 35.5 million km², something many don't expect considering that the Mongol Empire only reached 24 million. But here’s the interesting part: the Mongol Empire expanded faster, while the British were more strategic in maintaining their territories spread across the planet.

The Russian Empire follows with 22.8 million km², and if you think about it, that continental territory is much more cohesive than the British domains scattered across oceans. The Qing Dynasty of China reached 14.7 million, the Spanish Empire 13.7, and the French Colonial Empire 11.5 million.

What truly surprises is how different eras defined the biggest empire in different ways. The Abbasid and Umayyad Caliphates hovered around 11 million each, while Chinese dynasties like Yuan, Ming, and Tang varied quite a bit. The Yuan reached 11 million, the Ming just 6.5, but the Tang again reached 5 million.

If we look beyond the great empires: the Portuguese Empire with 10.4 million, the United States with 9.8 (considering territories after 1945), Brazil with 8.5, and even the Japanese Empire at its peak during World War II reached 8.5 million.

The fascinating thing is that when you talk about the biggest empire in the world, the answer depends on whether you’re talking about continental territory, dispersed regions, or actual influence. The British won in total extension, but the Mongol was more compact. The Russian Empire maintains more geographical coherence.

From the Achaemenid Persian Empire with 5.5 million to the Roman Empire with 5, including the Ottomans, Dutch, and even pre-Columbian American empires like the Incas with 2 million: each left its mark. The Byzantine Empire barely reached 1.5 million but lasted over a thousand years.

The history of empires is like this: the biggest wasn’t always the longest-lasting, nor the most influential the most extensive. But without a doubt, when you ask which was the biggest empire in the world, the British still hold the record that no one has surpassed.