Fence

Image 5 includes a fence
The fence is located near the site
And Verse 12 mentions the fence	Line 9 = "Fence and fixture"

M and B

M and B in verse 12 appear to reference Mozart and Beethoven, inscribed on the Theodore Thomas Orchestra Hall.

Theodore Thomas Orchestra Hall more or less directly across Michigan Ave from the casque site

Discredited Theories

• Man and Beast - it was thought that M and B stood for Man and Beast as a reference to the Bowman Statue. This is wrong because of Mozart above and M and B are set in bronze, not stone.
• Street Names - nearby streets intersection to the casque location begins with M and B, however this is not the intent of the clue.