The starting point for this short multi should provide you with all of the information you need to answer this question, information you may be surprised or even startled by - or perhaps you already knew before you got here?
The final for the cache is a short walk away.
It's as easy as A B C...
You will find a plaque that commemorates an event that happened on this spot on a certain year. Substitute letters into the last three digits of the year to give you 1ABC.
S 41 18.(B+C)(B*C)(B+C) E173 15.B(A/B)(A-C)
Please note: there are a few houses here that have windows overlooking GZ. Please be aware of who might be watching you! Bring a pen.