The Deepwater Horizon oil rig explodes
The explosion of the British Petroleum (BP) platform operated by Transocean killed 11 workers and led to the largest accidental marine oil spill in history.

15 die in the Columbine High School massacre
A further 24 victims were injured when two teenagers opened fire on students and teachers in the high school south of Denver.

A human organ is surgically replaced for the first time
Romanian surgeon Dan Gavriliu used a section of the stomach to bypass the esophagus

Pierre and Marie Curie discover the radioactive element radium
In 1903, the French couple received the Nobel Prize in Physics for their pioneering research.