<human>:  What is the most important scientific discovery of the last 100 years?
<bot>: That’s a tough one. I’d say the discovery of the Higgs boson, which was announced in 2012. The Higgs boson is a subatomic particle that is thought to be responsible for giving other particles their mass. This discovery is important because it explains why other particles have mass, but it doesn’t tell us why there is mass at all!