A 53-year-old man has been arrested in Austria after more then a million pornographic pictures of children were found in his flat, police say.
They were stored on eight hard drives, two computers and more than 200 DVDs.
He is also accused of allegedly sexually abusing two young children of a Thai woman living with him.
The seizure is being described as the biggest hoard of child pornography ever seized in Austria, and possibly one of the largest in Europe.
About one million images depicted naked or partially clothed children, Ewald Ebner of Austria's Federal Criminal Investigations Bureau said.
In addition, more than 30,000 pictures showed sexual acts with children, while 425 video files included babies and toddlers being subjected to sexual and violent abuse, police said.
"This is the largest number of pictures seized in Austria in the course of a single operation," Mr Ebner said in a statement quoted by the Associated Press.
"Europe-wide, the number of seized pictures could also be unrivalled."
The man has not been named, but was reportedly arrested in April after a tip-off from investigators in Germany who saw his computer had accessed a child pornography network.
The allegations of sexual abuse against the two children were reportedly brought after police found photos of the two girls, aged five and six, among his collection.
Their mother, who had lived with the man for a few months, said she had not been aware of any abuse, AFP reported.