The first record testifying the use of the “conserves” is a Venetian plan from 1643, they were useful to keep fish put between layers of pressed ice and snow inside masonry cylindrical truncated conical buildings with basements.
These constructions were surmounted by a square masonry space without windows, which isolated from the external environment.
On one of the sides a room, also square, was situated with a double door on the external side and a single one on the side of the funnel. The buildings, in order to be better isolated, were covered also on the roof with heaps of sand held by means of clods. The temperature inside the “conserves” was -5, -10 even in the summertime.