The worst terrorist attack in Japan’s history happened 30 years ago, on March 20, 1995, during the morning rush hour on the Tokyo subway system. Members of a violent cult called Aum Shinrikyo released packages of deadly sarin gas on several subway cars, killing 14 people and injuring several thousand more. Japanese authorities say the group remains an “ongoing problem.” The World’s Matthew Bell spoke with a woman in Tokyo whose husband was killed in the attack, and she has never stopped advocating for the relatives of the victims.