Couple finds $10m worth of old US coins while walking their dog in their backyard.

A couple found a stash of 1,411 gold coins worth $10 million while walking their dog in California

A couple found a stash of 1,411 gold coins worth $10 million while walking their dog in California

The stash is believed to have been buried on the property during the late 19th century Gold Rush.

Most of the coins were $20 gold pieces minted in San Francisco after 1854, but some were minted in Georgia, which is a mystery.

The coins were in immaculate condition and were never entered into circulation.

The origin of the treasure remains a mystery, but theories include it being the life savings of a miner, the remnants of a 1901 bank heist, or the hidden stash of a wealthy former resident who did not trust banks.

The identity of the couple who found the treasure and the current whereabouts of the coins are unknown.

The Saddle Ridge Hoard is the largest discovery of buried treasure in U.S. history.