by Aliya Whiteley

The oceans still hold many secrets. We're only just beginning to find ways to explore the deepest trenches, using technological advances to look at the strange creatures and landscapes that inhabit the total darkness found thousands of feet below the surface.

But though they've been difficult to access, there are also human artifacts at those depths—objects that have sunk to lie, undisturbed, for many years. Humans have been making boats since prehistoric times; who knows how many wrecks now lie in the deep?

The question of just how many wrecks lie in the deep is difficult to answer, but according to Guinness World Records, the deepest shipwreck that has been identified so far is a German blockade runner from World War II—the SS Rio Grande. In early January 1944, it was sunk by two U.S. ships in the South Atlantic Ocean. It lies at a depth of about 18,900 feet—more than 3.5 miles below the surface—and was discovered on November 28, 1996, using side-scanning sonar technology. Two days later, the company responsible for the find, Blue Water Recoveries, confirmed the wreck using a remotely operated vehicle.

It’s impossible to even guess at how many shipwrecks might yet lie in the deepest parts of the oceans (the Mariana Trench reaches a depth of about 36,000 feet). Just to give some perspective, more than 150 ships sank in January 1944 alone.

Not all sunken ships are wartime casualties, of course. One of the oldest shipwrecks found thus far was a cargo ship that was discovered off the coast of southern Turkey in 1982. The Uluburun wreck is 3300 years old. The cargo it carried has been recovered by divers, and included copper, tin, glass, ebony, weapons, food, elephant tusks, hippopotamus teeth, tortoise shell, and amber beads. Some personal items from the crew were also recovered, including a scarab made of gold that bears the seal of Nefertiti, wife of the pharaoh Akhenaten. It now resides in the Bodrum Museum of Underwater Archaeology. More recently, divers in Greece have found wrecks dating as far back as 525 BCE.

It’s staggering to imagine how many crafts, and how many people, must have been claimed by the sea over the centuries—that technology is now, finally, allowing us to find.