14 Man-Made Items Lost to the Bottom of the Ocean

Finding buried treasure isn’t a far-fetched idea when considering how many man-made items have gotten lost to the bottom of the ocean. You never know what you’ll find, and divers have made many unforgettable discoveries on the ocean floor.

Sometimes, the things found at the bottom of the ocean are valuable, while other times they’re financially worthless but are cool or interesting. These items can help us learn about history or fill in blanks from ship crash stories.

The items included in this list are man-made and can lead to intriguing research and discussions. Many other items have been discovered, but this list is of the ones that will surprise you.

1. Half a Billion Dollars’ Worth of Emeralds

Back in 2010, Jay Miscovich discovered an estimated half a billion dollars in emeralds — about 10,000 stones — in the waters off Key West, FL.

While he thought he’d be rich, he couldn’t cash in on his discovery. Once the media attention escalated, others wanted to claim the emeralds for themselves. It turned into a long legal battle that didn’t have the desired results.

2. Shipping Containers

Reports from the World Shipping Council show that around 1,382 shipping containers fell into the ocean yearly until 2019. After 2019, the number skyrocketed, and 2,675 got lost in only 14 months, but in 2022, only 661 went into the ocean. Their reports only tracked cargo accidents, so the true number is likely much higher.

The shipping containers that spill into the ocean can carry anything we want or need. Or they could move dangerous or illegal items. Either way, efforts should be made to reduce the number of containers lost to the ocean.

3. Ancient Greek Computer

At the beginning of the 20th century, a shipwreck off the Greek island of Antikythera was discovered. Here, divers discovered an ancient Greek computer known as a Antikythera mechanism,

The ancient computer could predict the positions of the stars, moon, sun, and planets. It is the only item of its kind that dates back to the second century B.C — 2,000 years before the tool was discovered at the bottom of the Aegan Sea.

4. An Astrolabe

Since 1998, divers have enjoyed exploring The Esmeralda, a ship that wrecked in the Arabian Sea in 1503.

Many treasures have been discovered over the years, but none have been as special as the astrolabe. Discovered in 2017, this is now one of 104 of these navigational devices still in existence.

5. Caesarea Treasure

Diving club members in the ancient harbor of Caesarea, Israel, found over 2,000 gold coins in 2015. These coins are over 1,000 years old, and the discovery became the largest in Israel.

No one knows where the coins came from or why they were on the ocean floor. The Israel Antiquities Authority collected them from the divers, so we may have more answers in years to come.

6. Jewelry

Plenty of jewelry has been lost to the ocean floor, from ancient artifacts to modern-day creations. If they were lost when a ship sank, like Titanic, they may still be down in the ocean, mixed in with the wreckage.

Depending on the weight and cut of the jewelry, it could end up in different places on the ocean floor. Sometimes jewelry washes up on shore far from where it was lost, but some pieces never resurface.

7. Thonis-Heracleion

Until 2000, Thonis-Heracleion was a mythical city. When scientists found the city under mud and sand in the Aboukir Bay near Egypt, they finally knew it was a real place.

This ancient city is close to the mouth of the Nile River. It was lost to the ocean because of earthquakes, tsunamis, and rising sea levels.

8. Ancient City of Alexandria

Pharaoh Cleopatra ruled the Ancient City of Alexandria until it was lost to the ocean floor. While the exact reason for it being submerged is unknown, it’s believed a series of natural disasters led to its end.

The ancient city was lost for nearly 1,600 years until it was found in the 1990s. There’s been discussion of turning the ancient city into an underwater museum by building tunnels for people to walk through.

9. Gold From the Gold Rush

The SS Central America, aka the “Ship of Gold,” wrecked off the coast of South Carolina in 1857. This ship earned its nickname not from being built from gold, but because of its cargo: gold from the California Gold Rush.

In 1988, Tommy Thompson discovered the wreck but wound up debating ownership of $50 million worth of gold in court. Without paying investors, he disappeared with the money before authorities found him in 2015. In 2014, another $40 million worth of gold was found and has been on display since January 2018.

10. Vehicles

In 1941, the SS Thistlegorm sank in the Red Sea, carrying army supplies for World War II. Amongst the supplies are old trucks. In other spots of the ocean, military tanks and submarines are found.

Other vehicles found on the ocean floor include motorcycles and planes. In many cases, no one knows how these vehicles got to their resting places.

11. Locomotives

There’s a locomotive graveyard off the coast of Long Branch, New Jersey, in the United States. This graveyard was discovered in 1985, with rare trains dating back to 1850.

The craziest part of this graveyard is that there’s no record of the trains existing or being dumped into the ocean. There are many theories about the origin, but no definite answers.

12. Christ of the Abyss

Christ of the Abyss is an ancient bronze sculpture of Jesus created by Guido Galletti. It was sunk in the Italian Riviera near the San Fruttuoso coast in 1954 to honor the first Italian to scuba dive using gear, Dario Gonzatt. It was also a dedication to anyone who died at sea.

Scuba divers and snorkelers frequent the site, and it has also developed spiritual significance. The statue has been removed from the water periodically for restoration and research but is always replaced in the same spot.

13. Cell Phones

Cell phones end up in the ocean in many ways, including falling from a boat or being dropped. Similarly, many snorkels, cameras, and anchors get lost on the ocean floor.

Accidentally dropping things into the water is common, so it’s no surprise the items gather below. Some divers gather these lost items to help protect the ocean and sea life, and surprisingly, they’ve found phones that still work.

14. Plastic Trash

Man-made plastic accumulates in the ocean, with some floating but much more sinking to the bottom. Experts say tons of plastic is on the ocean floor, including nets, cups, and bags.

Sometimes, the plastic breaks down into microplastics you can’t see without a microscope. Now, microplastics are in all ocean areas, even in the most remote places.