Unipiano

The Santuario dell’Unipiano stands on a glacial terrace, a remnant of the ancient valley floor shaped by the Sesia Glacier when it reached the Varallo area (red line in the image).

Following the retreat of the glaciers, the Valsesia valley floor was extensively eroded by the River Sesia, leaving only a few remnants of the ancient glacial landforms, such as the Unipiano terrace and the Sacro Monte di Varallo.

The Unipiano terrace is not completely flat because it is composed of both fresh rock and glacial deposits. Its upper part is made up of diorites: these hard rocks temporarily hindered the erosive processes and disrupted the flow of water, leading to the formation of a small lake. Subsequently, mountain streams eroded the fresh rock, and today we are witnessing the formation of a new gorge.