Wellcome to Potts Point! This is the neighborhood where I live and I wanted to create an special cache here.
If you have done more of my caches around town, soon you will spot the likely outer container of the cache, but to retrieve the cache itself you will have to come prepared with a tool. Easy! Just cut the top part of a plastic bottle, better if it is a 600ml one, as the big hole will have to cover your mouth tightly (as if it were a mask), so a 1L or 2L bottles will be too big for the task.
So, making the tool will be the "hard part" of the cache :) Once on the GZ, you will find where to screw your tool, and as the title of the cache page says: make a wish and BLOW!!!