A lifelong diver believes there are thousands of undiscovered sunken vessels off the Pembrokeshire coast.
James Hedley Phillips has found more than 30 of roughly 3,000 known wrecks, including a 15th Century trading ship and a coal freighter.
But he says he has barely scratched the surface of what lies on the seabed.
"With the equipment new divers will have at their disposal, there's still plenty out there for them to discover for themselves," he said.
During a career which began in 1968, Mr Phillips has dived off North Carolina, Florida, Israel, Corfu, France and Sri Lanka but says he is yet to find anywhere to compare with the unforgiving seas in west Wales.
"Pembrokeshire has always been infamous for the variety of its sea and wind patterns, so in previous centuries sail ships were utterly at the mercy of the elements.
"But when you add in dangerous rocks... then even modern vessels are vulnerable to a combination of features which you don't quite find anywhere else in the world."
He has now detailed some of his more extraordinary finds in his first book Pembrokeshire Trilogy, Tales of the Sea.
It also includes adventures discovering 1909 vintage wine worth £1,500 a bottle, which he drank before learning of its value, and coming face-to-face with a conger eel "as thick as a telegraph pole".
Fun aside, the Haverfordwest diver says there is a sombre side to his work.
"Every time you enter a wreck you have to remember that quite often it is someone's final resting place."
With the advent of modern sonar systems, the next generation of divers could have even more success with better kit at their disposal.
"All I can say is that often I'd start out looking for one ship, and end up finding a completely different one entirely by accident.
"But, in almost half a century, I've barely scratched the surface."