Yesterday was RH Day, celebrating the 150th anniversary of the publication of the Riemann Hypothesis with a series of lectures world-wide. In conjunction with this, the American Institute of Mathematics (AIM) has publish the AIM Problem Lists, listings of some of the most important outstanding problems in mathematics, which of course includes proving the Riemann Hypothesis.
Proving or disproving the Riemann Hypothesis is widely regarded as the Holy Grail of mathematics. In 1900, the legendary mathematician David Hilbert listed it as being among the most important unsolved problems in modern mathematics. Last year, DARPA included it in its list of 23 Mathematical Challenges. Settling the issue of the Riemann Hypothesis is also among the Clay Mathematics Institute's Millennium Problems.