The Rooswijk sank off the southeastern tip of England, just north of the Straits of Dover. The sea hides a most unusual feature known as the Goodwin Sands, where sandbanks appear and disappear unpredictably and move with the tides. Many ships over the centuries have sunk here and silted over, and occasionally, one of the wrecks will surface and be discovered. 
Such is the case with the Rooswijk, a Dutch East Indiaman that foundered on the Goodwin Sands in a storm on December 19, 1739, with all hands and 30 chests of treasure, virtually gone without a trace.
By chance, in December 2004, the sands that had swallowed the wreck of the Rooswijk parted and allowed Diver Ken Welling to retrieve two complete chests and hundreds of silver bars. Operating in secrecy, salvage continued in 2005 under the direction of Rex Cowan and in agreement with the Dutch and British governments and is ongoing today. 
So far, several hundred Mexican silver cobs of the 1720s and early 1730s and transitional “klippes” of 1733-1734, as well as many more hundreds of “pillar dollars” and a smattering of cobs from other mints, have hit the market from this wreck, mostly through auction.