(light gentle music) - Beneath this calm expanse lies a legacy of destruction.

(water splashing) Known as the Graveyard of the Atlantic, this single area contains over 5,000 shipwrecks, each one a stark reminder of the ocean's immense power.

Among them is the wreckage of a ship that sank in 1718.

Its captain was the English pirate Blackbeard.

Another victim of one of the most perilous coastlines in the Western Hemisphere.

This is the Outer Banks, a chain of barrier islands stretching hundreds of miles along North Carolina's Atlantic coast.

And this is a shipwreck.

Remains of ships like this one, whatever it is, are a haunting testament to the power of the sea.

(waves crashing) (dramatic orchestral music) The Outer Banks is a living landscape.

The dynamically changing coastlines that unearth this shipwreck also make this one of the most destructive places on Earth, not just for ships but for those who still live here today.

(building crashing) Just like the great ships of the sea before them, these tides now threaten roads, oceanfront homes, the existence of entire communities.

But what is it about this little spot on the Atlantic that makes it so dangerous?

And could our changing planet make these waters even more dangerous?

(car engine whirring) I am passing over Oregon Inlet.

It's named for a ship that narrowly escaped a powerful hurricane back in 1846.

That superstorm tore through this barrier island, literally ripping it in two.

(tense thoughtful music) This inlet, like the rest of the Outer Banks, is constantly shifting.

These moving sands create treacherous navigational conditions and require constant dredging.

It's these rapidly changing features that make this coastline so dangerous.

These morphing shallows of sand and sediment are known as shoals.

Shoals form underwater as waves and currents slow down, lose energy, and deposit sediment on the sea floor.

(light gentle music) While shoals are a defining feature of the Outer Banks, they aren't all bad.

They provide critical habitats for marine life like fish, crabs, and migratory birds.

They act as nurseries for juvenile species and support complex food webs, and they act as buffers between the Atlantic Ocean and the mainland by absorbing the brunt of storms and sea level rise.

(bright thoughtful music) The gentle slope of the Outer Banks's continental shelf creates an ideal environment for shoals as sand is pushed from deeper waters up onto the shelf.

Wave and tidal action move sand in and out of these shallow areas, redistributing sediment and often elongating shoals into ridges or bars.

Adding to this mix is the warm, fast-moving Gulf Stream current that converges with the cold Labrador Current off of Cape Hatteras.

This blend creates heavy turbulence and fluctuating water flow, depositing even more sediment.

This perfect storm of hydrology is what makes the Outer Banks so unpredictable and dangerous for navigation.

These forces are powerful enough to create entirely new islands and then destroy them.

Shelly Island sprang up suddenly in 2017.

At its peak size, it stretched over a kilometer and a half in length and over 150 meters in width.

After Hurricane Maria in late 2017, the island greatly diminished in size, and in less than a year, it had vanished like a ghost back into the depths of the Graveyard of the Atlantic, as so many ships did before it.

(gentle pensive music) (car engine whirring) Maritime history in this area goes back centuries.

Since the 1600s, sailors have used these waterways for fishing, trade, whaling, even warfare.

I'm on my way to meet up with a friend who knows a lot about this stuff.

The maritime historian, archeologist, and host of PBS's "Rogue History," Joel Cook.

(waves lapping) - Not far from here in Beaufort Inlet, Blackbeard and his crew, his two ships, are trying to evade the authorities.

(exciting dramatic music) They tend to sail smaller ships that have shallow drafts, so they don't have to be in as deep water.

And the Navy ships, that are heavy battleships, can't access these places where pirates can, and the shifting sands of North Carolina help them escape.

This ship that is known as the terror of the seas, you know, it's a legend already at this time period for Blackbeard.

And the Queen Anne's Revenge ends up running aground in Beaufort Inlet, and he's forced to abandon it and some of its crew as well.

The ship itself stays there until it's found in 1996 by a team of investigators.

- The Outer Banks have long been infamous for their ties to piracy, but that's just a fraction of their shipwreck history.

These waters have swallowed everything from Spanish galleons to Civil War ironclads and World War II freighters.

To dive deeper into this incredible history, Joel and I head to the Graveyard of the Atlantic Museum.

(light thoughtful music) How does this coastal region compare in terms of the number of shipwrecks to other places in the world?

- It really doesn't.

(laughs) You have a count of shipwrecks that starts here in 1526, and from that time period until now, you have 5,000 shipwrecks in this little piece of North Carolina.

- So this is just on a completely different level from other coastal points in the world.

- It's unbelievable.

(tense dramatic music) The USS Monitor, which is known as the first successful American ironclad, it wins the battle against the Confederate Merrimack, and it sinks close to here because of the conditions in this area.

At the tail end of World War I, the German Navy begins contributing to the Graveyard of the Atlantic with their infamous U-boats.

And the German Navy takes advantage of this by stationing U-boats around Cape Hatteras at a point that ends up being known as Torpedo Alley.

What they're able to do is use the lighting from the coastline in order to attack vessels because they can see the silhouettes of these ships using that light from the coastline.

These attacks continue into World War II, and though the US is aware of the German U-boats, they're not able to stop the onslaught of attacks on these convoys moving up and down the coast of North Carolina.

(radar beeps) - How much do you think is still out there waiting to be uncovered that we just don't even know about?

- I think there's tons.

If you consider those conditions haven't changed.

You know, the weather's still rough here.

The oceans are still rough here.

So it's hard for people like me and other archeologists to get out there and find every little thing.

Even in the sand dunes here, we have shipwrecks that are onshore.

People find new stuff every year.

You know, the sand dunes move, new shipwrecks are uncovered.

Others- - A shipwreck that nobody knew about, just emerging from the sand.

- Absolutely.

- Wow.

But while this coast remains treacherous, even to experienced sea captains, and continues to claim ships to this day, there is a new danger, one that we have to view from above, (bright orchestral music) From the air, the Outer Banks is just a fragile sliver of land next to an endless sea.

You can see the scars left by storms, the shifting inlets, the way the island bends and reshapes itself at the mercy of the ocean.

The shifting coastline doesn't impact just seafarers.

The towns and beachfront homes that dot this picturesque coast are now threatened by the same forces.

(waves lapping) These are homes literally being swallowed by the sea.

When these elevated houses were built, they were protected by stretches of dry sand and by dunes.

But a combination of wind, waves, and tides have brought the sea literally to their doorstep.

When waves and currents approach the shoreline at an angle, sand, and sediment are pushed up the beach in a zigzag pattern called longshore drift.

Over many years, this process can move entire beaches, putting homes in danger of literally falling into the sea.

Over the past four years, at least 17 homes have collapsed into the waves.

Since officials have been monitoring this area, this coastline has eroded by 10 to 15 feet per year.

And who knows, weeks or months from now, these houses will be reclaimed by the ocean.

(gentle atmospheric music) This coastline has always been unstable and flood-prone, but climate change threatens to make it even more treacherous.

Storms and hurricanes that are more severe, along with rising sea levels, will have a major impact on the communities in the Outer Banks, in some places threatening their very existence.

Is it only a matter of time before these barrier islands become consumed by the sea?

Possibly.

The shifting nature of the Outer Banks makes the land and sea difficult to predict.

Climate change and the effect that humans are having on our oceans and atmosphere only make those challenges harder to deal with.

Change is a constant on the Outer Banks.

Humans have sometimes failed to navigate that change, and the disastrous consequences are still visible beneath the waters as a warning sign to future generations.

But today, as our actions change the planet as a whole, the survival of the communities and ecosystems that call this coastline home, that'll require more than just steering through the shifting sands.

(waves lapping) (bright tense orchestral music)