A: The 1858 Historic Landmark Flag Pole!7011 Vine Street. It's been moved a few blocks from it's original location at Seymour and Vine where it stood in front of the Avenue House, a 19th century hotel and tavern founded by a German immigrant named H.H. Lammers. I'm not sure if he was related to the Nazi War Criminal with the similar name and initials. The nearby plaque didn't say and Google wasn't any help.
The pole sat there being a pole for over 100 years displaying all the different American flags in great fashion starting with the 32 star US flag until the Sun Oil Company wanted to put a gas station in the old hotel's spot. I know you are thinking "boo! bad oil company people! boo!" However, I am happy to report that the Sun Oil Company was a good sport and paid to have it moved up the street to its present location in 1970. The citizens of Carthage then celebrated their fantastic historic wooden flag pole with a big party on Flag Day. I'm sure it was a great celebration.
Then in 1982 it was designated a Cincinnati Neighborhood Landmark, making it the city's smallest historic landmark!
If anyone is working on creating "Trivial Pursuit: Cincinnatus Edition" this should definitely be included.
In case you were wondering...nope, there is no geocache here. I was just driving by and saw the sign.