Fermilab's Tevatron accelerator (near Chicago) will close down today, as the latest particle physics research has shifted to the Large Hadron Collider in Europe. According to this
Chicago Tribune article, the Tevatron "made major contributions to physics, including the discovery and precise measurement in 1995 of an essential building block of matter called the top quark, and the discoveries of five subatomic particles known as baryons and another called the tau neutrino."