What is a Wapaniki???

Ok, so we saw this map and Sylwia checked it out thoroughly.  We could go sightseeing and see the "Wapaniki".  What is this I asked her?  Well, in a nearby village of Golina we found out, but even after studying it on the internet, we really don't know what it was...except that a Jewish man "created" the Wapaniki and was successful.  So was it a storage place or what was it??? 
You tell me!
Well, since posting Christoph Sottor sent me a link (German one) to the Wapaniki

This is the church in Golina, adjacent to the Wapaniki....