This is Alvin.

Alvin is a quirky deep-sea submersible  that changed marine science forever. Alvin was the first sub that allowed scientists  to both see AND sample the ocean floor.

Alvin is so iconic that even today,   more than 60 years later, it’s STILL being  used to explore the bottom of the ocean. The way Alvin came to be,  though, isn’t what you’d expect. It wasn’t built by a traditional submarine  producer like General Dynamics Corporation.

And it wasn’t built by some massive  aerospace company like Boeing, either. It also wasn’t built by a defense  contractor like Lockheed Martin. Instead, Alvin was built by General Mills.

That’s right. The Wheaties company. [♪ INTRO] Humans have been on Earth  for at least 300,000 years. And for pretty much that entire time,   we’ve been trying to explore one of the  greatest wonders of our planet: the ocean.

But exploring the deep-sea has proven to  be a lot more complicated than we thought. Most of our historic exploration has  been limited to the ocean’s surface. But we’re a pretty stubborn species, so we  invented diving bells … basically open bottomed,   bell-shaped contraptions that trap an air  pocket inside it for people to breathe.

Diving bells allowed humans to get  deeper than they ever could on their own,   but they couldn’t get THAT deep still. So, we invented submarines and submersibles. Submarines can operate independently,  while submersibles usually rely on   another vessel to shuttle them around  and act as a home base essentially.

Modern subs came around in the 1920s, with better  materials for handling deep ocean pressures. These could get us to the seafloor  independently, but they had a major limitation,   which is they usually had no windows, and  they couldn’t collect or sample anything. So starting in the 40s and 50s, we put  windows in something called the bathyscape.

It could survive the pressures of the deep ocean,   and you could actually see the  ocean while you were down there. But again, it had one major flaw: We could only  look, we couldn’t really sample much from it. That’s because sampling arms would  have created a weak point in the hull.

A geophysicist named Allyn  Vine was working at Woods Hole   Oceanographic Institution or WHOI at the time. And he thought there had to be a way to do both. He wanted to build the world's first deep-diving   submersible that could see  AND sample the seafloor.

So in 1962, he convinced the leaders at  WHOI to call for bids to do that. Any company that believed it was capable of  designing and building a deep sea sub could apply. And there were two final contenders … one was  aerospace manufacturer North American Aviation,   and the other was none other than General Mills.

Today, we know General Mills as a cereal company. They make Cheerios, Wheaties, and  most importantly, Lucky Charms. But they’ve been around since 1866,   and they’ve actually dabbled in a lot  of different products during that time.

They’ve made clothing, toys, and boardgames. They even helped create early versions of the  recording black boxes that are used in airplanes. So it actually wasn’t THAT crazy for them to show   interest in a side project like building a deep sea submersible.

When the bid from General Mills came in at almost   $100,000 lower than its rival,  they were given the contract. A cereal company was about to build the first  ever manned submersible for scientific research. They decided to name it  Alvin, in honor of Allyn Vine.

Work on the submersible began in the same  room as the equipment that made the cereal. The original design looked something like this. And you can see that compared  to the sleek military subs   people were used to seeing, Alvin is a bit… tubby.

But there were very good reasons for its shape. Inside the sub’s frame, there was a  set of batteries, a buoyancy sphere and   variable ballast that enabled the sub’s  vertical movement in the water column. Outside the frame, there was a rear  propeller and rudder for steering,   the lift propeller, light and sonar  equipment, and a robotic arm for sampling.

But the most important design  element was a new feature to   address the crushing pressure of the ocean. The best demonstration I can give for exactly  how much pressure we're talking about is this. This is a styrofoam cup, or at least  it was before the ocean shrunk it.

It’s a tradition in deep sea science to  decorate styrofoam cups and tie them to   the outside of a sub before an  adventure to the ocean floor. So the pressure of the deep  sea inevitably shrinks the cup. It’s kind of like an ocean shrinky-dink!

To deal with all that pressure and  still give scientists a view of   the ocean floor, Alvin designers added  a personnel sphere made of titanium. The reason a sphere works so well is that it’s  one of the most pressure-resistant shapes. The compression is evenly distributed   across its entire surface, which  prevents weak points in the sub.

Titanium is also considered the best  material to withstand deep-sea pressures. Its high strength-to-weight  ratio is better than steel’s,   and it has equal strength in every direction. This makes it even more resistant to compressive  forces than materials like carbon fiber.

When Alvin was completed in 1964,  it was an engineering marvel. And it wasn’t long before it was being used to  make all kinds of amazing deep sea discoveries. Arguably the biggest discovery was in 1977,   when a group of geologists were studying  a location called the Galapagos Rift.

They towed a camera behind their ship and caught  a glimpse of something shimmering in the water. Previous research had suggested that  there might be hydrothermal vents here. Those are places where circulating seawater  water is superheated by magma in the Earth's   crust before returning up to the  seafloor through deep sea vents.

They sent Alvin down to investigate  whether this was true, and what they   found had never been seen anywhere else on Earth. Huge. Colonies.

Of life. More than 2500m deep in the ocean. Giant Mussels.

Species of crabs and deep sea  octopus completely unknown to science at the time. And huge stalk-like tube worms that were bigger than anything known to marine biologists before. There were small spherical animals they called   “dandelions" that used web-like fibers  to sit above the ocean floor and feed.

And all these images are the original photos  taken from that first dive to the vents. It was an incredible discovery. But there was one problem.

They were geologists, so they hadn’t brought  any equipment to store biological specimens in! In fact, there wasn’t a single biologist on board. One of the greatest discoveries in modern history,  and it was a bunch of rock people who found it.

Since they didn’t have any formaldehyde  to preserve the biological specimens,   they did exactly what you’d expect a  bunch of geologists in the 70s to do. They stored the specimens in the  Vodka that they had brought with them. The smell of the water they brought  up from the vents provided a clue as   to how these creatures could survive  in the darkness of the deep ocean.

It didn’t smell like normal seawater. It smelled like rotten eggs. That smell was hydrogen sulfide  coming out of the vents.

It had been feeding bacteria, and an  entire ecosystem had developed around it. An ecosystem almost completely dependent  on life without any photosynthesis. Alvin played a huge role  in revealing how these vents   form from volcanism at mid-ocean ridges.

Mid-ocean ridges are a place on  the earth's surface where two   tectonic plates are moving away from each other. Magma, which becomes lava at the surface,  comes up between these two plates. It's a 65,000 km long chain of underwater  volcanoes running across the entire planet. 70% of Earth’s surface, almost our entire ocean  floor, is formed by volcanism at mid ocean ridges.

And when eruptions happen underwater, the  lava hardens into all kinds of weird shapes. You get lava flows that look  like pillows, folded curtains,   and lavas that look essentially  like its been hacked into pieces. Being a very creative bunch, marine  geologists have named them pillow flows,   curtain folded flows, and hackly flows.

You can even get whirlpool-shaped rock on  the ocean floor made by tiny lava whirlpools. If you’re wondering why everything in these photos  has a faint shine to it, that’s because the top   layer of the lava crust is a kind of volcanic  glass called mid ocean ridge basalt, or MORB. That’s right: A lot of the  ocean floor is covered in glass.

Even though MORB glass is incredibly common,   few people have heard of it because  it’s all at the bottom of the ocean. Some of my favorite features  that Alvin has explored along   mid-ocean ridges are lava drips and lava pillars. Lava drips form when water gets trapped in  the molten rock and is vaporized by the heat.

This hot steam in the now solid lava  crust actually re-melts the underside   of that crust and causes it  to drop through the vapor. And then these are Lava Pillars. From a distance they almost  look like ancient ruins,   but these aren’t man made … they’re volcano made.

They form when the trapped  seawater can't vaporize. It wants to escape from the lava,  but the lava heats it up and causes   the water to geyser up and out of the lava itself. As it does, it rapidly cools the lava all   around it into what looks like  a straw made of volcanic rock.

As the lava slowly drains out of this area  and leaves a hollowed out lava crust behind,   it leaves rings like water  might leave on your bath tub. These rings are prized by scientists  who use them to study how the chemical   makeup of the lava changes throughout an eruption. Countless other discoveries  have also been made from Alvin.

In 1986, it dove to the site of the Titanic  shipwreck to investigate the debris field. In 2010, it explored the site of  the Deepwater Horizon Oil spill   to study the impacts that had on marine life. Alvin even worked with the US Navy to recover  a lost Hydrogen bomb at the bottom of the sea.

Since its launch, Alvin has taken more than  14,000 scientists and pilots to the ocean floor. I got to be one of them during  the first year of my PhD! In fact, this shrunken cup I showed you earlier is  the one I made to commemorate my first Alvin dive.

I dove on Alvin Dive 5245 to a depth of  2,565 m at my favorite mid ocean ridge,   the East Pacific Rise. I traveled with an incredible research team in  2024 for what we called the lava watch cruise. We were looking for signs of a new  volcanic eruption on the ocean floor.

We didn’t find any, but we did discover  five new hydrothermal vents and the cooled   remains of a giant underwater lava lake  I’m currently attempting to write a paper on. The eruption we were looking for  did eventually happen a year later, though. And it was captured on camera by, you  guessed it, the Alvin submersible.

Alvin has had a lot of upgrades over the years,   but ultimately, it’s still the same  quirky sub from all those years ago. It has bigger windows, and it can  now go down to 6,500 m deep,   reaching 99% of the ocean floor. It probably won't happen in my lifetime,  but with vehicles like Alvin, I can’t   help but believe it’s only a matter  of time before we’ve finally seen all of it. [♪ OUTRO]