The Renon earth pyramids are the highest and best formed in Europe. They are a phenomenon of erosion, formed from glacial moraines. When dry, this moraine clay is as hard as stone, but when dampened it forms a porridge-like substance and slips downhill.
To the earth pyramids on the Renon mountain. A dream-like excursion for children: first of all by cable car to Soprabolzano, then taking the olde-worlde narrow track railway across the Renon high plateau, finally to marvel at the famous obelisks of red earth and rocks at Longomoso, the earth pyramids.
This builds up steep cliffs, which form the pyramids when large stones contained in the moraine protect the mud below. The protected areas remain hard and the rest slips into the valley. With each rain a little more is eroded. When the protecting stone falls, however, the unprotected pyramid rapidly disappears.
The earth pyramids are found in three valleys on the Renon, the Finsterbach between Longomoso and Maria Assunta, in the Katzenbach valley below Soprabolzano and in the Gastererbach valley near Auna di Sotto.