Eight years ago, we received an e-mail from a teacher asking for a list of all of the stones embedded in the facade of the Tribune Tower.  Neither she, nor we, were able to find a full list on the internet, so we spent half a day wandering around what was then the home of the Chicago Tribune, jotting down the rocks. The resulting article, listing all 149 rocks, is now our fifth-most-read article, with over 13 million views. Tribune Tower (file) A few months later, someone pointed out that there was actually 150 rocks in the Tribune Tower.  Number 150 was in the lobby: a rock from the grotto...