It's early morning, and I'm in Crammond, a quaint former fishing village on the outskirts of Edinburgh, Scotland.

Picture postcard pretty, its quiet main street leads down to a row of whitewashed three-story houses,

hugging the banks of the River Alund, which is dotted with little

one-mass boats. Crammond is a place rich in history. It's a former Roman outpost, where

archaeologists have also found artifacts from the Mesolithic era, meaning it may be the

oldest human settlement in the whole of Scotland.

I spent a lot of time here as a child growing up in Edinburgh, but I'm not here today to visit Crammond itself. I'm standing on the promenade, looking toward the Firth of Fourth, the river

estuary which separates Edinburgh from the Kingdom of Fife to its north. My eyes are drawn across the

water to a place of mystery and adventure that has lingered in my consciousness for decades. Crammond

Island. I'm Nick Dawson and this is Atlas Obscura, a celebration of the world's strange, incredible, and wondrous places.

Crammond Island has had a peculiar sort of hold on me for as long as I can remember.

As a kid, I was awed by this seemingly unreachable island.

And it became something of a symbol of the childhood I wished I'd had.

Today, I'm finally going to explore it. That's after this.

Okay, so the tide time's here.

My wife Heather is coming along with me on my Crammond Island quest. We're going to walk across the causeway, a mile-long raised concrete path, which leads from the mainland to our destination.

Crammond Island is a tidal island, which means it's accessible on foot only when the tide is low.

At high tide, the causeway is entirely submerged.

I remember as a kid looking out at the island with distant longing whenever I visited Crammond Village.

But weirdly, my memories do not include the causeway. Instead, what I see in my mind's eye

is just an expanse of squelchy sand stretching

out endlessly. My memory seemingly also erased another pivotal detail, the line of huge,

...