Scientists know that galaxies and clusters of galaxies are held together by what they call “dark matter.” This mysterious stuff can’t be seen, yet it comprises five times as much of the universe as all the ordinary matter that makes up our world, our bodies and the sun. But what is it really? We will start by viewing the feature- length movie Particle Fever, which shows the behind- the -scenes story of the Large Hadron Collider (LHC) in Switzerland where the Higg’s particle (Nobel Prize 2013) was discovered. The LHC is currently searching for clues as to what dark matter is. We will discuss various theories about this priority physics and cosmology problem, along with some novel technical jargon.