While preparing the existing floor for the new pouring I discovered remnants of the old building.
In its latest years (circa 1970-1980) it was used in a wine bottling operation as a storage room and later my grandad started to build a small studio for my uncle (but that project was cancelled due to things better not to speak of).
Before that, around the 30’s and 40’s, the whole house was a ceramic tile factory. Giant ovens to fire the clay, castings and all that.
As I started to dig the trench for the new waste plumbing I found what looked like the walls of a chamber or well of sorts. The top was made of reinforced concrete and had all the appearance of being a lid.
I tried to break and lift it with very little success. On the other extreme of the room there’s a hole that seemed to be a small opening made on purpose. I dug with my hand but only got sand, gravel and fragments of old tiles.
I gave up as whatever I removed from the floor had to get back and then some more to make a proper base layer for the next one. But I plan on digging further later on.