Vienna, Austria (BBN)-Austrian police are trying to work out how the Danube river was turned from blue to red and green by tens of thousands of scattered euros.
More than €100,000 (£71,755) in €500 and €100 notes were spotted floating down a section of the river in Vienna at the weekend, reports the Sky news.
They were discovered by a boy who jumped in the river to retrieve the cash, according to Oesterreich newspaper.
Bystanders thought he had jumped in to kill himself and alerted police, who were able to fish out the cash.
Detectives have reportedly ruled out money-laundering and any other criminal activity as the source of the money.
Police spokesman Roman Hahslinger said if no one came forward to claim the cash it could be claimed by the boy who found it on Saturday.
Under Austrian law, if the rightful owner is not identified within a year, he can claim it all.
The Danube originates in Germany’s Black Forest before flowing east through Austria and several other countries and emptying into the Black Sea.
It stretches to more than 1,700 miles.