Almost every culture on earth has independently invented a dragon — the Chinese with their long river-serpents, the Norse with Nidhogg gnawing at the world tree, the English with Saint George's fire-breathing beast, the Aztecs with Quetzalcoatl the feathered serpent.

Why does the same creature keep appearing in cultures that never met?

One theory is that every early human society had three real animals to fear: the biggest snake in the swamp, the biggest cat in the grass, and the bird of prey overhead.

Combine them and you get a dragon.

Another theory is fossils — a farmer ploughing up a huge dinosaur bone in ancient China had no other word for what he was seeing.

Chinese dragons, tellingly, are wingless and swim like giant snakes; European dragons have wings and breathe fire.

Two very different dragons for two very different landscapes.

Try this: draw a dragon of your own.

Notice which real animals you borrowed pieces from without meaning to.