A COUPLE in America have discovered hidden treasure in their humble little backyard, unearthing more than $52,000 worth of valuables.

Matthew and Maria Emanuel, from New York, say they were excited after finding a rusted, rotting metal box submerged in dirt at their Staten Island home while having new trees planted.

They were then stunned to learn the box was actually a safe which included wads of wet $100 bills and bags stuffed with diamonds, gold and jade.

“I thought, ‘we found buried treasure!’” Mr Emanuel said, according to the New York Post. “We were freaked out. It’s something you can’t make up.”

Also inside the safe was a Brooklyn address written on a note inside one of the bags — which the Emanuels linked to one of their neighbours.

“We realised it must have been them, so Monday morning, I walked on over to their house and knocked on their door,” Mr Emanuel said.

“I asked them if they’d ever been robbed.”

The neighbours told him they had nearly seven years ago.

The NYPD confirmed that the safe was stolen during a burglary at the neighbours’ home in 2011, according to CBS.

The owners of the safe declined to comment — but were thrilled to have their stuff returned, the Emanuels said.

“She was like shaking and hugging me,” Mr Emanuel said of the woman.

Mrs Emanuel added, “A couple of people asked us, ‘Why did you return it?’ It wasn’t even a question. It wasn’t ours.”

The safe’s owners blamed the robbery on the notorious “Ninja Burglar” who was convicted of 160 robberies on Staten Island.