Forty years ago, renowned treasure hunter Roger Miklos claimed to have discovered one of Adolf Hitler’s lost U-boats on the ocean floor off an island in the Turks and Caicos. During World War 2, Nazi Germany’s U-boats – or submarines – plagued the Atlantic Ocean, sinking more than 1,500 Allied ships, many of which were ferrying crucial supplies to Britain from North America and the Empire.

       The conflicts became known as the Battle of the Atlantic, which lasted from 1939 until the end of the war in 1945.

       The Allied forces struck back during this period and sunk more than 600 German submarines.

       However, the sunken U-boat Mr Miklos claimed to have found was not just any German submarine, but one of a specially modified fleet of nine deep-sea cargo-smuggling vessels constructed towards the end of the war.

       He astonishingly claimed that the U-boat was packed with looted gold, priceless artworks, and even the bodies of high-ranking Nazi officials.

       Mr Miklos never revealed the exact location of his alleged discovery, but the late explorer left behind a cache of secret documents as to the U-boat’s whereabouts.

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       The treasure hunter and former police officer died from a heart attack in 2018, but in his final interview he laid out the significance of his discovery.

       In archived footage, he says: “This is the find of a find of a lifetime, it beats Tutankhamun and anything else.

       “There ain’t nobody going to find anything better than that.

       “It’s been missing for 72 freaking years.”

       The footage is used in a new season of the History Channel US docuseries, ‘History's Greatest Mysteries’.

       The programme is narrated, and executive produced by US actor and director Laurence Fishburne.

       The second episode, ‘Hunting Hitler's U-Boats’, revolves around new efforts to track down Mr Miklos’ lost U-boat.

       Diver and explorer Mike Fletcher, who leads the investigation, received a call out of the blue from Mr Miklos’ family.

       They handed over the treasure hunter’s cryptic stash of evidence, which Mr Fletcher and his team of experts poured over.

       Speaking for the documentary, the expert said he was open to many of Mr Miklos’ claims about the plundered Nazi treasure.

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       He said: “We do know that there’s billions of dollars in looted personal possessions.

       “Gold, all sorts of valuable material that went missing during the war.

       “It certainly made sense that some of this could have been loaded on the U-boats to smuggle them out of Europe and into a safe haven.”

       None of the alleged secret fleet of Nazi U-boats were ever found, until Mr Miklos reported his discovery in 1981.

       Speaking in his last interview, the treasure hunter said: “They welded all the torpedo hatches up, removed all the torpedoes for cargo, for all the treasure.”

       Mr Fletcher and his team began their investigations last year, although they were disrupted by the COVID-19 pandemic.

       Their access to the secret documents, turned over by Miklos’ family, is the first time that anybody other than him has seen the records of the lost U-boat.

       History's Greatest Mysteries is available on the History Channel US.