In 1900, twenty-three unsolved mathematical problems, known as Hilbert’s Problems, were compiled as a definitive list by mathematician David Hilbert. A century later, the seven most important unsolved mathematical problems to date, known as the ‘Millennium Problems’, were listed by the Clay Mathematics Institute. Solving one of these Millennium Problems has a reward of US $1,000,000, and so far only one has been resolved, namely the famous Poincare Conjecture, which only recently was verified. Now a negative solution to one of Hilbert’s problems has been found. Mathematicians are working on the more challenging of maths problems — and the only one that appears on both lists — Riemann’s zeta function hypothesis.