When I moved to the near south side of Chicago, right away I wanted to find out where the Union Stockyards used to be. This historically famous place is now just acres after lonely industrial acres of bottling plants and truck storage facilities (see this Google map), with the exception of the limestone gateway still standing in its original location.
I was surprised to stumble across this old tourist's pamphlet from 1903 which gives an interesting glimpse into what passed for tourism at one time. In its heyday, seeing the assembly line slaughtering of animals at the Yards was a "must" for any visitor to Chicago.
Thanks to Sharon Williams' Chicago History blog, where I found this.