One of the four mysterious heads of Medusa. There are well over 300 columns to support the subterranean cistern, but two of these columns are unique, like this one, because they rest on reused (brought from another ancient Roman building) blocks of stone carved with the likeness of Medusa. One of them—this one—is sideways, and the other is upside-down. Historians are divided as to what it means. It's what makes history so fascinating! Who knows WHAT it means? Everyone's got an opinion. What's yours? Every other column is normal, except these two. Why?