It's difficult to express just how fracking impressive the Large Hadron Collider is. You really have to be there to understand how overwhelming and ginormous it is. Still and all, maybe the video I took of the tour will help get the idea across (if you go to that YouTube page, there is a link right under the video that allows you to watch it in higher quality. I recommend doing that).
ATLAS and CMS are detectors, built to detect the shrapnel from the collisions of protons moving just a whisper slower than light itself. For the cast of characters and a description of this tour, take a look at my earlier post describing it. There are pictures there from the journey as well.