Mark Klein, a former AT&T technician, has passed away. He was a whistleblower who revealed the NSA's mass spying program in 2006, providing evidence of a secret room at AT&T's San Francisco office where internet data was being copied and delivered to the NSA. Klein's revelations led to lawsuits and reforms, and he is credited with helping to inspire a movement towards greater privacy and transparency. His legacy continues to influence efforts to reform surveillance and protect personal privacy.