ZetaGrid was at one time the largest distributed computing project, designed to explore the non-trivial roots of the Riemann zeta function, checking over one billion roots a day. Roots of the zeta function are of particular interest in mathematics, since the presence of even a single one that is out of line with the rest would disprove the Riemann hypothesis, with far-reaching consequences for all of mathematics. So far, every single one of them has failed to provide a counterexample to the Riemann hypothesis.