A few weeks ago, I showed remnants of a World War II-era bunker on the coast of New Hampshire. People seemed to have some real interest in it. A little research showed more extensive fortifications nearby. I took a drive there during the Christmas break for a sunrise shoot.
This set of two connected gun emplacements was in the woods. Several paths led to the clearing. The concrete was covered with dirt to make it look like a hill. At the top was a blockhouse that may have served as a room from which to direct the firing of the guns.
More information about the history of Fort Dearborn can be found here.