Oh, dirty, dirty dirt. We feverishly rinse you off our vegetables, we wipe and wash to prevent you from settling in our homes, and we even keep our precious pups from rolling in you (as much as possible, that is). But even with all of these efforts, your ubiquitous presence ever haunts us — and somehow we still don't know that much about you! What are you made of? Where did you come from? What do you have against cleanliness? These and other questions will be answered... More >>>