Very close to the old town of Anagni exists an ecosystem that has remained unchanged for millennia: that of the Rio stream.
The Rio is, as its name suggests, a torrent that arises in the mountainous area north of Anagni, the famous Ernici Mountains named for the pre-Roman people who lived there. In its bed the Rio digs very deep channels between sandstone layers before reaching the plain and converging into the trench of the Mole, which in turn throws itself into the river Sacco.
The Rio is formed by several branches and the one that comes from Mount San Giorgio is the steepest. On this mountain are still the remains of a medieval fortification, along the ancient route that connected the cities of Anagni and Acuto.
This branch of the Rio has given rise to particular phenomena: one element that drew the morphology of this environment was the abundant water supply during the last glaciation that ended about ten thousand years ago.
The most characteristic element of the Rio are the so-called bowls, in which one can recognize the “giant dixies”, a kind of large cooking pot. These are deep-wall depressions present in the rocks, which arise from river erosion, in the presence of large amounts of water and a steep slope.
Arriving with a certain impulsiveness, the water torrent carries a large amount of crushed stone and at the points where a vortex is formed, the pebbles, thrown with force against the rocky wall, erode it. Thus, over the millennia, these wells have been dug. Obviously, the essential condition was that the gravel transported was harder than that of the rock bed of the river.
The name “giant dixies” comes from ancient popular beliefs. It is said that these regular openings in the rock were the enormous cauldrons used by giants to prepare their meals.
These legends could be associated with others that relate to the construction of the imposing megalithic walls, also known as Cyclops, that are widespread in this area of Southern Lazio
In any case, ‘marmitte’ (dixie) is an evocative geological formation that takes on particular brilliance with the flow of water and deserves the walk to visit and photograph them. Unfortunately, the Rio is currently in serious deterioration, due to illegal waste and discharging, which is affecting its beauty.
The ‘dixies’ are present in other Italian regions, particularly in those of the Alpine areas, where they are always a great tourist attraction. In the province of Frosinone they are found in the gorges of Melfa, in the valley of Canneto and in the Grottos of Falvaterra.