In trendy downtown Tempe, Arizona, stands the shell of what used to be the Hayden Flour Mill. The historic hulk, which occupies the southeast corner of Rio Salado Parkway and Mill Avenue (appropriately), can be seen up close. There’s a small park adjacent to the building and there are placards along the outside detailing the history of the place. You can even peek inside through the windows to survey the all machinery abandoned and left in place. According to the City of Tempe, the site is awaiting appropriate redevelopment.