A Newport man has been searching a landfill site in south Wales hoping to find a computer hard drive he threw away which is now worth over £4m.
James Howells's hard drive contains 7,500 bitcoins - which is a virtual form of currency for use online.
It had sat in a drawer for years and he had forgotten it contained the bitcoins, which he obtained in 2009 for almost nothing, when he threw it out.
But this week, a single bitcoin's value hit $1,000 (£613) for the first time.
It means Mr Howells's collection is now worth $7.5m (£4.6m).
A few years ago Mr Howells, who works in IT, had dismantled his computer after spilling a drink on it.
"I stored a couple of parts away like the hard drive, and the rest of the bits and pieces which were still working I sold for spares," he told BBC Radio Wales.
"I kept the hard drive in a drawer in my office for three years without a second thought - totally forgot about bitcoin all together. I had been distracted by family life and moving house.
"Fast forward to 2013 which is when I had a clearout of my old IT equipment - I hadn't used this drive for over three years, I believed I'd taken everything off it... so it got thrown in the bin."
Mr Howells later realised what was left on the hard drive.
He added: "I had been hearing a few stories of a chap from Norway who had bought a number of coins for a very low price and had sold them for a high price and that's when I got back into checking the price and seeing what I'd done.
"When I found out what the price was, the penny dropped and I realised the coins I have 'mined' were on the drive I had thrown away.
"There was not a lot I could do."
Mr Howells checked all of his back up files but could not locate the coins so went to the landfill site in south Wales.
"When I went to the tip the manager took me up to the current landfill site and when I saw it - it's about the size of a football field - my first thought was 'no chance'," he said.
"The manager explained that things that were sent to landfill three or four months ago could be three to five feet deep.
"He confirmed my worst fears when he said that.
"He did mention that when people were investigating for evidence, they turn up with 15 to 20 people in full protective gear with diggers and dogs as well.
"The truth is I haven't got the funds or ability to make that happen at the moment without a definite pay cheque at the end of it."
In a letter to the US Senate committee, the FBI said that it recognised virtual currencies offered "legitimate financial services" but added they could be "exploited by malicious actors".
In October, the world's first bitcoin ATM opened in Vancouver, Canada. The machine allows users to exchange bitcoins for cash and vice-versa.
The virtual currency has also been quickly adopted in China, where one exchange - BTC China - is said to be the most active globally.
Bitcoin's use in China has been attributed to it being an effective way of reliably getting money out of the country.
Various bitcoin exchanges have been set up around the world, with MTGox - one of the virtual currency's major exchanges - being the most prominent.
Mr Howells added: "I still believe in bitcoin. I believe its value is going to go much, much higher and it's still in its early days.
"As soon as access to bitcoin is opened up to the general public I think a lot more people will be using it, hence the price will increase further."