Over 200 elementary particles have so far been seen in particle accelerators, though most are so unstable and short-lived that they can barely be said to exist at all. Within the next few years, physicists hope to start discovering a whole slew of new particles using the Large Hadron Collider (left) near Geneva. This gigantic underground machine has the power to find so-called supersymmetric partners of familiar particles such as the electron, which are predicted to exist by attempts to unify the fundamental forces of nature.