To find the world's oldest anything, you wouldn't expect to find it in one full piece.
But one ship has proved otherwise.
A Greek trading ship, dating back to 400 BC, has been discovered off the Bulgarian coast, making it the world's oldest known ship.
The 75 ft vessel was discovered by a team of researchers at the Black Sea Maritime Archaeology Project (Black Sea MAP).
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It was part of their three-year-long survey of the seabed to study prehistoric sea level changes.
Using advanced mapping technology, the team identified 65 shipwrecks across more than 2,000 square kilometres of seabed.
A researcher on the expedition, Helen Farr reported: 'It’s like another world.
'It’s when the ROV [remotely operated vehicle] drops down through the water column and you see this ship appear in the light at the bottom so perfectly preserved it feels like you step back in time.'
Despite lying 1.25 miles below the surface for thousands of years, the ship still retains its rudder, rowing benches and even the contents of its hold (which remain unknown for now).
How is this possible?
It's all about oxygen levels.
If you've ever been scuba diving, you know that the deeper you go, the less oxygen there is.
In this low-oxygen environment, organic materials like wood and cargo can be preserved for thousands of years.
'A ship surviving intact from the classical world, lying in over 2km of water, is something that I would have never believed possible,' said Professor Jon Adams, the principal investigator with the project.
'This will change our understanding of shipbuilding and seafaring in the ancient world.'
The team plans to let the ship rest undisturbed at its final site but took a small sample to accurately carbon-date its age.
'It's preserved, it's safe,' Farr added.
'It's not deteriorating and it's unlikely to attract hunters.'
Though this is the oldest intact shipwreck, it's just one of many prehistoric relics the team has discovered at the bottom of the Black Sea.
One of which includes a '17th century Cossack raiding fleet, through Roman trading vessels, complete with amphorae, to a complete ship from the classical period.'
The research team said more funding would be needed if they were to return to the site.
'As archaeologists, we're interested in what it can tell us about technology, trade and movements in the area,' Farr concluded.