Horizon goes behind the scenes at CERN to follow one of the most epic and expensive scientific quests of all time: the search for the Higgs particle, believed to give mass to everything in our universe. 　　However, the hunt for Higgs is part of a much grander search for how the universe works. It promises to help answer questions like why we exist and is a vital part of a Grand Unified Theory of nature. At the heart of the pursuit of the elusive particle is the same feature that makes snowflakes beautiful and human faces attractive: the simple and enchanting idea of symmetry.-------------（@BBC Two）