I guess for me, I believe in dragons...but not as you would think.

I think the world has had civilizations more advanced. Evil takes over and they destroy themselves. Wash, rinse, repeat.

That said, I believe those, like the Rothschild family, only unknown and higher up the food chain, keep the tech. Normal people go back to Stone age living.

So as the peasants live, and see a fighter jet for example, can't explain them. The jet engines roar, fire flies out of it's mouth and destroys villages in the form of missiles, etc.

Think about a submarine that surfaces directly below your wooden boat, destroying it, the eye of it's periscope surfacing first.

I think this, among other things, is what is hidden from us.

I think that is partly where we get monster lore from.