The European organization for Nuclear Research (CERN) has been building the Large Hadron Collider for many years, but it's finally taking shape and prepping to operate at full power in 2008. The New Yorker has a great feature and slideshow on the collider, which it describes as the best and possibly only hope "for testing the theories of 'new physics' against material reality."
The superconducting collider is located in a circular tunnel with a 17-mile circumference on the Swiss French border. When it's fully functional, it'll speed up atoms to velocities never before achieved, smashing them into each other with the hopes of finding particles never seen before, including the one that gives matter its mass. That particle, called the Higgs boson, would show that "the void of space is not really void but is permeated by an invisible field that acts a bit like cosmic molasses." Still with me? No? Go take a look at these pictures anyway: Scientists have built something enormous and crazy underground.
Via The New Yorker