A California couple out on a walk with their dog found $10 million worth of gold coins buried at the base of an old tree on their property. Presumably to avoid a miniature gold rush of treasure-seekers descending on their land, the couple has chosen to keep their names and exact location quiet. Instead, a firm specializing in gold coins announced the discovery on behalf of the family. Kagin's Inc. believes it could represent the "greatest buried treasure ever unearthed in the United States." 

According to Kagin, the face value of the gold coins adds up to about $28,000, but their condition and rarity sent their expected value soaring. The 1,400-odd mint-condition coins date from 1847 to 1894 and come in denominations of $20, $10 and $5. Some of the individual coins in the collection are probably worth upwards of $1 million each. Until the California find, the biggest buried gold treasure haul in the U.S. was believed to be a 1985 discovery by construction workers in Tennessee. It sold for about $1 million, as The Los Angeles Times noted. 

Understandably, the couple described the find as "surreal": they noticed the top of a rusty can buried in the ground, presumably uncovered by erosion. After digging up and opening the can to find the treasure inside, the couple went back to the same spot and found several more cans, all filled with gold. "I thought any second an old miner with a mule was going to appear," the husband of the anonymous couple added. There were few clues at the site as to who left tens of thousands of dollars buried under a tree.

The couple will sell most of the very valuable coins, of course. According to Kagin, they're planning to do that on Amazon through the online retailer's collectibles store.