In late 2013, a hoard of silver coins worth a combined £34 million ($50 million U.S.) was raised from a shipwreck located about 500 miles off the coast of St. Helena in the south Atlantic, but the effort has only come to light, according to The Telegraph.

The 100 tons of silver rupees were onboard the SS City of Cairo when the ship was sunk by a German sub during its trip from Bombay to England in 1942, The Telegraph reported April 14. They had been buried 17,000 feet under the ocean's surface. 

Deep Ocean Search, the the company that was contracted to carry out the recovery effort, claims the depth, which is more than 4,000 feet deeper than the Titanic wreck, is a world record for a recovery.

The silver rupees belonged to the United Kingdom Treasury.

"The U-68 struck the slow-moving steamship with one torpedo but waited a further 20 minutes before inflicting the coup de grace, thus allowing all but six of the ship's 302 passengers and crew to escape on to lifeboats," The Telegraph reports.

According to the DOS website, the company began looking for the wreck in November 2011 and left the site for good on Sept. 25, 2013, after the recovery was completed.

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