Anyone want to hazard a guess as to what these are?  It's another thing tres Louisiana..... happily some of the women  I was riding with had been on a Mississippi Tour could identify these mud castles as crawfish homes!  They build them to get air into their underground homes, I think.  There's lots of mud here, and one of our riders saw one of these towers with racoon prints leading up to it - seems like a really easy snack.   Today we rode past some cemetaries with above ground crypts, apparently built this way because of the high (ie close to the surface) water table.