Which particle accelerator first exceeded a teraelectronvolt?

The Tevatron at Fermilab, outside Chicago, which ran from 1983 to 2011 and reached about a trillion electronvolts per beam - hence the name. It was the highest energy collider in the world for a quarter of a century until the Large Hadron Collider started up.

Its great discovery was the top quark in 1995, the last of the six and by far the heaviest - about as massive as an entire gold atom, which was unexpected enough to matter for the theory. It also produced precision measurements of the W boson mass that constrained where the Higgs had to be, which told CERN roughly where to look.

The Tevatron also invented the technology everyone now uses. It was the first accelerator built with superconducting magnets at scale, which is the only way to bend a beam that energetic, and for a period Fermilab was the largest consumer of liquid helium in the United States. It was shut down in 2011 for budget reasons, months before the LHC found the Higgs - and the American plan to build something bigger, the Superconducting Super Collider in Texas, had been cancelled in 1993 with a fifth of the tunnel already dug.