An Adelaide sex tourist branded "a child's worst nightmare" for his abuse of 11 babies and children has been jailed for a record 40 years.
Ruecha Tokputza, 31, groomed children for sex in Australia and Thailand, filmed their abuse and shared it online.
Prosecutors have said his crimes are the most serious case of sex offending in Australia, and District Court judge Liesl Chapman on Friday called him a predator whose actions were depraved.
She sentenced him to 40 years and three months behind bars, with a non-parole period of 28 years, after he pleaded guilty to 50 charges committed between 2011 and 2018.
It's the longest sentenced imposed for child sex offences in Australia.
"You are a child's worst nightmare, you are every parent's horror, you are a menace to the community," she said.
"Unfortunately there are many like you out there, fortunately you have been caught."
The majority of Tokputza's victims lived in Thailand, where he was born before he migrated to Australia when he was 13 years old.
Judge Chapman said his youngest victim was just 15 months old, and Tokputza removed one child's nappy to abuse him while he slept.
She said Tokputza believed he was helping the children by "showering them with love, care and attention".
"You said you knew what you did was wrong because they were underage, but you never saw yourself as hurting them," she said.
"You felt you took care of them and they loved you back."
In addition to the sex offences, Tokputza was caught with 12,500 images and 650 videos of child exploitation he had downloaded.
He also had 415 images 251 pornographic videos that captured his own crimes taking place.
Judge Chapman said the material was proof that child pornography was "not a victimless crime".
She said a psychologist had found Tokputza met the full criteria for a pedophilic disorder, and was at a medium to high risk of sexual reoffending.
Prosecutors last month said they could not find a child sex case as serious as Tokputza's in Australia, including that of notorious Families SA sex offender Shannon McCoole.
McCoole was in 2015 sentenced to 35 years in jail -- with a non-parole period of 28 years -- for sexually abusing babies and young children in state care.
Tokputza will not be eligible for parole until he is in his late 50s.