A stash of gold coins found by a Californian couple whilst walking their dog could be worth over $11m. The first coin was auctioned last night at the Old San Francisco Mint, with the remainder going on sale on Amazon and Kagins.com later this month.

Numismatist, Don Kagin, valued the coins and believes it is the biggest find in U.S history. It is unclear who buried the coins but the gold would have been minted by the San Francisco Mint. The couple, who wish to remain anonymous, plan to pay off their debts and make a large donation to charity.