Note: This episode contains descriptions of child sexual abuse.A monthslong New York Times investigation has uncovered a digital underworld of child sexual abuse imagery that is hiding in plain sight. In part one of a two-part series, we look at the almost unfathomable scale of the problem — and just how little is being done to stop it. Guests: Michael H. Keller, an investigative reporter at The New York Times, and Gabriel J.X. Dance, an investigations editor for The Times. For more information on today’s episode, visit nytimes.com/thedaily. Background reading: Last year, tech companies reported over 45 million online photos and videos of children being sexually abused. Lawmakers foresaw this crisis years ago, but enforcement has fallen short. Our reporters investigated the problem and asked: Can it be stopped?Tech companies detected a surge in online videos of child sexual abuse last year, with encrypted social messaging apps enabling abusers to share images under a cloak of secrecy.Here are six takeaways from The Times’s investigation of the boom in online child sex abuse.