Hundreds of people were arrested around the world after a child pornography Web site selling horrible videos in exchange for digital money was seized and closed.
The alleged site leader, a 23-year-old South Korean named Jong Woo Son, along with 337 users in 12 different countries, has been charged so far.
South Korea's website, Welcome To Video, relied on bitcoin cryptocurrency to sell access to 250,000 child sexual abuse videos, including young children being raped.
Its submission page specifically stated, "Do not submit adult pornography," according to authorities.
Officials from the United States, Britain and South Korea described the network as one of the largest child pornography operations they had ever encountered.
Assistant US Attorney General Brian A Benczkowski said: "Darknet websites that profit from the sexual exploitation of children are among the most vile and objectionable forms of criminal behavior."
At least 23 underage victims who were actively abused by site users were rescued in the US, Britain and Spain, the Justice Department said.
Many children in the videos have not yet been identified.
The site had a vast library of images never before seen by police, and is an example of what authorities say is an explosion of online sexual abuse content.
Britain's National Crime Agency said authorities are seeing "increases in severity, scale and complexity."
The site is one of the first sites to monetize child pornography using bitcoin, allowing users to hide their identities during financial transactions.
"These are primarily responsible for the criminal world," said Don Fort, head of the IRS's criminal investigation who initiated the investigation.
The site collected at least $ 370,000 in bitcoin before it closed in March 2018.
Darknet sites, such as Welcome To Video, were designed to be impossible to find online, and it is still unclear how authorities were able to locate and topple the site.