Ransomware is proliferating across the country, disabling computer systems and harming critical infrastructure — hospitals, city governments, schools, even an oil pipeline. The technology that enables ransomware may be new, but extortion and ransom are not. So why is this happening now? And can it be stopped? In this 5-part series from MIT Technology Review and ProPublica we look at the money, people and technology behind the explosion of ransomware that is delivering hundreds of millions of dollars to cybercriminals around the world. Hosted by Meg Marco.