A Greek merchant ship dating back more than 2,400 years has been found completely intact and lying on its side off the Bulgarian coast.
The 23m (75ft) wreck, found in the Black Sea by an Anglo-Bulgarian team, is being hailed as officially the world's oldest known intact shipwreck.
The researchers were stunned to find the merchant vessel closely resembled in design a ship that decorated ancient Greek wine vases.
The rudder, rowing benches and even the contents of its hold remain intact.
"It's like another world," Helen Farr from the expedition told the BBC.
"It's when the ROV [remote 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."
The reason the trading vessel, dating back to around 400 BC, has remained in such good condition for so long is that the water is anoxic, or free of oxygen. Lying more than 2,000m below the surface, it is also beyond the reach of modern divers.
"It's preserved, it's safe," she added. "It's not deteriorating and it's unlikely to attract hunters."
The vessel was one of many tracking between the Mediterranean and Greek colonies on the Black Sea coast. It was discovered more than 80km off the Bulgarian city of Burgas.