The top quark was discovered in 1995 at Fermilab, the end result of a few decades of decidicated hunting by various groups around the world, using ever-more-powerful accelerators, detectors, and analytic systems.

The mass of the top quark is about 175 GeV, close to that of an entire gold atom. This explains the difficulty in producing such quarks; the collision energies inside the particle accelerators must be incredible to allow particles of such mass to be born.