(This contest has ended, but you can read the answers here.)

We all love a mystery, don’t we? But our readers especially seem to like our mystery photo contests, so we thought we would try another one. This time, we have upped the ante with 15 new puzzlers for your consideration.

As usual, the entrant with the best overall submission will be the winner. Please get your submissions in by midnight (Central time) Monday, October 21, 2013.

The winner gets a copy of the CERA book A Rainbow of Traction.

Some of you seem to prefer writing about your guesses on public forums. You do so at your own risk. You might just provide another entrant with the winning answer.

Good luck figuring out our puzzlers, which are all from the Chicago area this time.

-David Sadowski

#1 – This picture was taken in Chicago during fall 1958. But what is it? Where is it? (Photo by Charles L. Tauscher, Wien-Criss Archive)

#2 – What is this? Where are we? When could it be? (Photographer unknown)

#3 – Where are we? (Photographer unknown)

#4 – What have we here? When was this picture taken? (Photographer unknown)

#5 – Where was this picture taken? (Photographer unknown)

#6 – What is this? (Photographer unknown)

#7 – What is this? (Photographer unknown)

#8 – Where are we? When was this picture taken? (Photographer unknown)

#9 – Where are we? (Photographer unknown)

#10 – Where are we? When was this picture taken? (Photographer unknown)

#11 – What station is this? (Photographer unknown)

#12 – Where are we? (Photographer unknown)

#13 – Where are we? (Photographer unknown)

#14 – What station is this? (Photographer unknown)

#15 – Where are we? (Photographer unknown)