The Justice Department has announced the conclusion of Operation Grayskull, one of the largest joint crackdowns in history against online child exploitation networks. Working with the FBI, prosecutors secured 18 convictions and dismantled four of the most “egregious” dark web platforms ever uncovered.

Authorities say these sites were visited by more than 120,000 users worldwide, some featuring content so extreme it shocked even veteran investigators. The platforms were run like criminal corporations, complete with moderators, posting rules, and encrypted communication channels to evade law enforcement.

Sentences have been severe: one Minnesota man received over 20 years, while another defendant from Michigan was sentenced to 55 years. Others, including site moderators, drew sentences ranging from 23 years to life in prison.