If I mention them to you, the first thing you'll think of is aliens, and that would be wrong.

Sadly, that's the first thing most people imagine when they hear about crop marks.

They see elaborate patterns, flattened stocks, and something that looks like a corn maze.

But crop marks are actually something else.

Yes, they are patterns visible in a field, but their origins aren't from up above, or even from tricky locals.

No, these crop marks originate from below.

And it all has to do with archaeology.

Here's how it works.

In places where there used to be a ditch that became filled in over time, the crops planted above those spaces have more fertile soil than the areas around it.

So in times of drought, the plants growing above those ancient ditches look more green and lush.

Wherever there are walls, though, the opposite happens.

The soil there is more shallow than other areas.

So during the drought, the plants growing above them look dead and yellow.

And if you add in the invention of the airplane, you have a recipe for discovery, which is what has happened in England for decades.

There are far too many examples to list here, but every time the weather gets overly dry and hot in the English countryside, it becomes possible to fly over normally green fields and spot shapes.

The outlines have long forgotten buildings, the contours of a Roman road, even the ring shaped remnants of ancient Iron Age burial mounds.

Through crop marks, we can see how the archaeology below has an influence on the world above, and it's incredible.

But sometimes the opposite has been true.

For thousands of years, the things above us have altered the way we live our lives down below.

It's a realm of folklore that might seem boring and predictable, but in reality, it's one of the darkest homes of our weirdest behavior.

And I promise you this, you'll never look at the sky the same way again.

I'm Aaron Mankey, and this is lore.

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