Last week's Mystery Spot was scant challenge to eagle-eyed Spotters. Yep, as BF, Joe, and cmadler correctly guessed, it's a sliver of the former Luna Lake in Prospect Park.
This week we're venturing a bit westwards to this site that at one time was situated right off Washtenaw. This building was torn down in 1917 and replaced by another building that in turn was torn down in 1979. What was the original building's function? Take your best guess and good luck!