A man arrested in California for currency smuggling has been found in possession of counterfeit bills with a face value of $1bn.
The $100 bill is currently the largest in circulation
US customs agents said they had found 250 of the bogus bills at the man's West Hollywood apartment.
Officers discovered the stash of wrinkled notes with an issue date of 1934, bearing the image of 19th-Century President Grover Cleveland.
The highest bill currently made in the US is for $100.
The police discovered the fake money when they searched the apartment of Tekle Zigetta, 45, on other charges.
An elderly couple who lived in the apartment told agents they kept the bills for Mr Zigetta while he was abroad and thought the notes were authentic, AP news agency said.
"You would think the $1 billion denomination would be a giveaway that these notes are fake, but some people are still taken in," said James Todak, a secret services agent involved in the investigation.