Historical Events
- Discover of gravitational waves (through collision of two black holes) announced by physicists from the Laser Interferometer Gravitational-Wave Observatory (Ligo)
- Last of Oregon militia occupying Malheur wildlife refuge surrenders to authorities after 41 days
- Riot between rival drug cartels at a prison in Monterrey, Mexico, leaves 52 dead
- Sixth Democratic presidential candidates debate, broadcast on CNN and PBS, and held in Milwaukee, Wisconsin