Anyone who has flown over the Edisto area of South Carolina may have looked down and noticed these unusual ring shaped structures and the marshes below.

What are they exactly?

How did they get here?

Who put them there?

Find out on this episode of Curiosity Trek!

Mysterious ring structures...

The remains of ancient civilizations such as these dot South Carolina's coastline.

Edisto in the Lowcountry is the home to three unique ring structures.

This particular cluster is called Fig Island.

But what are they?

They were constructed by Native Americans thousands of years ago.

I'm your host, Andrew Davis.

Today, we will dig a little deeper into the history of these shell rings.

But first, we had to make the trek down to Edisto.

Adding to the challenge, the rings are no longer publicly accessible.

So we needed a little help from the South Carolina Department of Natural Resources to get there.

From our home base in Columbia, South Carolina it's a two hour drive to make it to Edisto.

Upon our arrival, we embarked on a 15 minute boat ride out to Fig Island.

Even after our boat landed, the journey wasn't over yet.

To see these rings up close, we had to make our way through a lightly wooded maritime forest environment.

Like a scene straight out of an adventure movie we weaved through vines, avoiding various species of spiders.

With the help of Sean Taylor, Senior Archaeologist for the SC Department of Natural Resources we arrived at our destination.

These shell rings, what are they?

That's a good question.

We don't know.

We don't know if they're ceremonial centers we don't know if they're habitation centers we don't know what their purpose were.

There's 20... More than 26 of them on our coast.

Just a few miles of here, there are several.

There are three rings here at Fig.

Fig 1, 2, and 3.

Fig 3 is a crescent.

Figure 2 is a hexagon shape And Fig 1 is a series of rings that make up a big complex.

There's a historic map that has the words which look like"Pig Island", actually so I think Fig Island is a... Somebody transcribed it erroneously perhaps sometime in the 19th century.

They're made up of oysters and tons of other shellfish.

Every shellfish species you can think of through excavation, we will recover from each ring.

It doesn't seem to be a big difference in species diversity between rings.

The wonderful thing about the shellfish is it's allowed for the preservation of a lot of other stuff.

The flora and fauna remains that we get and shell rings are really incredible.

That's something that we don't get on other sites.

Rings primarily tell us about their food ways; what kind of resources they're collecting from the natural world, and they're eating everything that moves, swims or flies, and things that don't move.

Now, similar structures have been found off the coasts of Georgia and Florida... Could you kind of compare the rings found here to the ones found in states further down from us?

Our rings in South Carolina tend to be circular or crescent in shape and tend to be about 200 to 300 feet in diameter.

Some of them are very low, and we think that probably has to do a lot with agricultural practices in the 19th century when they were farmed.

Raw oyster shell was used as a building material for Tabby.

We see that happening a lot so we think that some of the rings have been depleted in that way.

So you get rings that are only a foot or two in height and unlike Fig here, which doesn't appear to that to ever happen, Fig 2 is about 6 to 7 feet in height and 250 or so feet in diameter.

Rings on the Florida Georgia coast, the north Georgia coast look a lot like the rings in South Carolina.

They're circular in shape and similar in size- some small, some of them bigger.

But as you move south along the Georgia coast they become more amorphous in shape and they look more like the ones in Florida which are often really very large much, much larger in size and oval in shape.

The Fig Island Ring Complex is around 4,300 years old in age.

To compare that with other famous landmarks they're about the same age as Stonehenge in England or the 3 Ancient Egyptian pyramids of Giza!

Now, out of all the materials available to these Native Americans, why did they pick oysters, of all things?

I think it's their abundance in the natural world they're just so abundant.

Then we've looked at historic maps to see how abundant our historic oyster beds were and we see that we don't have the oyster populations today that were here even 200 years ago and much less 4000 years ago.

So they were just here for the taking.

In order to build a massive shell ring it would take millions of oysters consumed over a long period of time!

Thankfully, when you have a whole village of people all eating the same food, it doesn't take near as long to accumulate the number of shells to build a ring like this.

Once again, thank you for taking the time to come out here and share these fascinating facts, Sean!

Absolutely any time I've enjoyed the day.

Although some unanswered questions remain about the true purposes of these rings, perhaps further archaeological studies will reveal more clues.

We hope you enjoyed learning about these captivating structures at Fig Island.

What do you think they were for?

I'm Andrew Davis, and we'll see you next time on Curiosity Trek!