Caglieron Caves Park


The Caglieron Caves Park is one of the identifying symbols of the Municipality of Fregona, in the province of Treviso, where nature and human activities are perfectly intertwined.

The Caglieron caves are what remains of a quarry area: a splendid example of environmental recovery and restoration.

Within the gorge carved by the Caglieron Stream, there are numerous waterfalls, several meters high, with large basins at the base, carved into the rock by water erosion. In the deepest part of the gorge, large limestone concretions are visible on the walls, partially closing the vault, giving the whole appearance of a cave.

On the walls of the gorge, large artificial cavities open up, obtained from the extraction of sandstone, the typical "piera dolza" (soft stone). The extraction activity, dating back to 1500 and perhaps even earlier, provided material for the construction of door jambs, lintels, etc., which can still be observed on the old houses and buildings in Vittorio Veneto and its surroundings.

The extraction method was interesting: as the layers were inclined at angles exceeding 45°, the material detachment, caused by using large chisels that left visible marks, occurred in blocks, with the precaution of leaving inclined columns to support the vault. This resulted in a series of suggestive artificial cavities distributed along the gorge, at the bottom of which the stream flows swiftly and noisily, leading to the construction of an equipped path.


Opening hours: From May to September: 09:00 AM - 06:00 PM From October to April: 10:00 AM - 04:00 PM

Contact: EMAIL WEB PHONE 0438 585487 CELL 328 8117359

We want you to have a pleasant and safe experience. Please respect other visitors and help keep the park clean!

General Behavioral Rules

Order no. 14 dated 06/26/2018
  • Do not litter
  • No open fires
  • Do not pick flowers, plants, or stones
  • No inappropriate footwear
  • No climbing. Do not lean over the walkways
  • No running
  • No bathing
  • No bicycles allowed
  • No strollers allowed
  • Walk only on the trails, in single file, and avoid crowding
  • Children under 14 must be accompanied by an adult
  • Dogs must be on a leash (maximum length 1.5 m)
  • Keep a muzzle handy
  • Pick up after your dogs and use dedicated bins


Why "Caglieron"?

Because the Caglieron Stream has carved basins at the base of the waterfalls, resembling pots, locally called "cagliera," used for making polenta. The basins have become deeper due to the swirling motion of water, moving pebbles and other debris, progressively digging them deeper.

The stream has masterfully shaped a short canyon (gorge), cutting perpendicularly into the Fregona Ridge, which has naturally inclined rock layers of about 40° due to the uplift created by the birth of the Alps.

The gorge is the result of a partial collapse of the hillside that got wedged into the V-shaped incision created by the stream. In fact, the stages of creating a cave are three:

  • First stage: The watercourse, flowing and carrying debris, carves the gorge (a small canyon). The walls on the sides are very steep and rugged.
  • Second stage: A upper section collapses from the side walls: the debris gets stuck halfway up the wall, forming a kind of "roof" over the gorge.
  • Third stage: Rock and plant encrustations with calcium carbonate form.

Today Caglieron, yesterday a large river delta

Starting from about 190 million years ago, there was a warm tropical sea with lagoons and coral reefs like the present-day Bahamas. When the Alps began to form, everything deposited under the sea, animal shells, and calcareous sand, started to emerge and rise due to tectonic pressures between the African and Eurasian plates. This gave rise, around 40 million years ago, to the Fregona Ridge, whose limestone is still the basis of the Park.

The plant species found in the Caglieron Park are typical of wet and shady environments and contribute to the uniqueness of the Park. The vegetation on the gorge walls is made up of species that are quite rare in the Veneto region.

Visiting the Caglieron Caves is like entering the gravelly and sandy deposits of ancient and large rivers. On some walls, you can see lighter sediments that are shell fragments embedded in sandstone, a rock consisting of compacted sand formed about 11 million years ago. It means that there was a sea-like environment here, a beach of a large river delta dominated by sea waves, similar to the current delta of the Piave River. In this rock, many fossils of gastropods (such as snails), bivalves (mollusks with a double shell), and echinoids (such as sea urchins) can be found.

The water of the Caglieron meets the sulfur springs Along the stream bed, there are small sulfur springs that emit the classic smell of "rotten eggs". They are home to some colonies of sulfur bacteria, algae, diatoms, protozoa that feed on the chemicals dissolved in the water, sometimes producing whitish filaments.

Stalactites and stalagmites: Nature decorates space

Water is a great artist and creates particular morphologies above and below ground depending on how it flows and how much time it has to shape. Karst is a natural phenomenon of chemical corrosion of rock by rainwater, which shapes the limestone rock by consuming it.

Concretions are the decorations of caves. In this case, rainwater accumulates in pools and infiltrates the rock, permeating into an underlying cave: in this way, instead of corroding and digging, it encrusts the surface of the cave itself, gradually depositing layers of calcite with a temperature of 12°C and 95% humidity. Stalactites are those that descend from the top down, while stalagmites are those that stand on the floor. When they join together, through dripping, which is the drop falling in the cave, columns are formed. The baby stalactite is called a straw and consists of a kind of spaghetti or canal along which water flows.

Formation of Travertine

It is a carbonate deposit that grows on the waterfalls of the Carron Stream with the collaboration of plants. The name derives from the Latin lapis tiburtinus, meaning "stone from Tivoli," where they are particularly developed. Some of these deposits are often also referred to as "calcarenite." Travertines have a vacuolar structure (characterized by numerous small cavities) largely due to the voids left by incorporated plants, subsequently decomposed.

The genesis of travertines is mainly due to the action of bacterial forms that, through photosynthesis, remove carbon dioxide from the water, favoring the precipitation of calcium carbonate in the form of encrustations.

Cave Pearls

They are spheres of calcium carbonate (calcite) that can have a diameter of up to one centimeter. Light beige in color, they consist of a succession of concentric layers (like an onion) grown through crystallization on a starting nucleus that can be a grain of sand. They are generated by the continuous rolling caused by dripping or moderately energetic flowing water. They are found in groups of different sizes inside submerged basins fed by oversaturated water. A necessary condition for the pisolith (the set of granular crystals) not to cement to the floor is to be subject to continuous movements or vibrations.


Dipper (Cinclus cinclus)

It can remain submerged for a long time in search of food thanks to some strategies: "special goggles" to see underwater, a kind of semi-transparent third eyelid, and an insulating "diving suit," plumage constantly impregnated by the bird with an oily secretion to ensure waterproofing. Outside the water, you can admire its dark brown plumage all over the body and wings, except for the large contrasting white spot under the throat and chest.

Caddisflies (Trichoptera)

They are insects that live most of their lives in water in the larval form. They are also known as "casebearers" or "caddisworms" because the larvae construct a protective case along the entire abdomen with natural material, such as grains of sand and pebbles, glued together by an invisible thread of viscous silk. Adults have wings covered in hair. Trichoptera in Greek, in fact, means hairy wings.

Fire Salamander

Don't eat me! That's the message the fire salamander wants to convey to its predators with the vibrant coloring of its mantle. Indeed, on a shiny black base, the salamander features a contrasting speckling of lively yellow spots. This amphibian with a sinuous body resembles a lizard, but its skin is dotted with small glands secreting irritating mucus. The mucus serves a bactericidal function, reduces dehydration, and has a repellent taste for potential predators. It is ovoviviparous; females give birth to larvae in an advanced stage in water. The larvae inhabit fresh, slow-flowing, and well-oxygenated waters.

Harvestmen (Opiliones)

They are arachnids known for their long, slender legs and very small bodies. They are elegant and move gracefully like dancers. They are not spiders, although some may confuse them: the abdomen, in fact, is not separated from the rest of the body by a thin peduncle but is fused together. They lack venom glands and silk.

Italian Wall Lizard (Podarcis siculus)

It is the largest lizard we have in Italy (45 cm in length). It has bright colors ranging from green to yellow, with a slight dark reticulation, and during the breeding season, the throat turns sky-blue. It is active during the day but is difficult to spot because it hides and is very fast at running and climbing.

Field Cricket (Gryllus campestris)

Also known as the singing cricket, it is easy to hear its chirping while walking in the summer. The songs change depending on the weather: they are faster when it's warmer. The stridulation is produced by males rubbing their wings against each other. The body is compact, with a fascinating brown color with coppery reflections.

Slowworm (Anguis fragilis)

Slender, shiny, and bronze-colored, it looks like a snake but isn't! Instead, it is a legless lizard. Like the lizard, it can lose its tail and regenerate it. It is ovoviviparous; the mother can give birth to 6 to 12 offspring. It mainly feeds on snails and small invertebrates.

Garden Snail (Cornu aspersum)

The silvery mucus produced by its foot (the scientific term for its body) is used as a lubricant to avoid injuring itself. The mucus is also useful for humans: it is used to reduce minor scars and wrinkles, in cough syrup, to alleviate burn pain, and improve skin regeneration.


Bats are the only mammals capable of flight; their scientific name is "Chiroptera," which means hand-wing. Their wings are formed by two thin layers of skin stretched over the arm and elongated fingers. They navigate in space thanks to echolocation – and two large ears - but they are not blind; they see in black and white.

River Crayfish

The River Crayfish (Austropotamobius pallipes) is a crustacean that is rarely observed.


Caves, whether natural or artificial, would be the ideal place for plant life: air saturated with humidity and almost constant temperature. However, light, as we know, is essential for photosynthesis. Progressing from the outside to the inside of the caves, we find flowering plants up to the entrance or just beyond, such as wall pellitory. Ferns follow (maidenhair and spleenworts, with long curled leaves) that reproduce in 1/300 of the light compared to external brightness. Even more tolerant are mosses with 1/1000, and finally, algae at 1/2000. At the inner limit of each zone, the specimens become smaller, delicate, and sterile.

Moist Environments

Water, light, and temperature are the fundamental elements for life. During the journey, it will be evident how they interact with each other and how the different availability of one compared to the other conditions plant life. However, water plays the role of modifying the territory: digging gorges, shaping slopes, and depositing pebbles, sand, and silt where the current slows down. This allows biodiversity to express itself: you can easily come across a sediment bed colonized by hygrophilic vegetation (which loves water), represented by alder (a tree with serrated leaves), willow, sedge (a herbaceous plant with characteristic spikelets), and bur-reed (robust aquatic herb).

Gorge Environments

On steep, shady slopes, moistened and refreshed by the flow of water, the most representative vegetation consists of herbaceous species such as Sesleria (an evergreen with thin ribbon-like leaves) and Cinnamon (a small marsh cane with a shrubby appearance), while the forest becomes sparser with struggling trees. In this type of environment, it is not uncommon to come across plants that normally grow at higher altitudes, such as common tofieldia or Sesleria itself, which is a building species of limestone meadows located above 1800-2000 meters.

Dry Slope

Immediately outside the humid gorge, there is a brighter and sunnier place where the soil is shallow and lean, and the rock emerges in some places. In these conditions, the abundant precipitation is quickly drained away, and plants often face water scarcity. Therefore, xerophilic flora (which loves dryness) prevails, morphologically predisposed to make the most of the little water available through special adaptations: highly developed roots and stiff or hairy leaves to reduce transpiration, or succulent herbs resembling small succulent plants, such as borage, with a shape reminiscent of coniferous twigs.


The rocky wall that looms almost vertically over the waterfall and the pathway is adorned with a rich community of ferns, giving the place a tropical appearance. The ivy draping down in festoons from the cave's vault strengthens the connection. The population consists of common hart's-tongue fern, maidenhair spleenwort, and Fortune's holly fern. The first has long, distinct, and slightly curled leaves. The second is characterized by a delicate appearance due to small, round light-green leaves. The third, Fortune's holly fern, is recognizable for fronds divided into triangular lance-shaped segments; it is native to East Asia. Cultivated for ornamentation, it has integrated into these environments without competing with the native flora (naturalized species).

Alien Plants

Some of the plants encountered along the trail do not belong to the local (indigenous) flora but originate from non-European countries, introduced by humans for food, productive, or ornamental purposes. This flora, defined as alien or allochthonous, manages to establish itself where natural vegetation has been altered by human activities (cultivation, quarries, urban areas), spreading through communication routes or watercourses. They are often invasive species such as tree of heaven, black locust (locally known as cassia), or Buddleia cultivated as an ornamental plant for its imposing fragrant inflorescences and now invasive in riverbeds and streams.


Inside the park, you can encounter riparian formations of Common Alder (Alnus glutinosa) and Grey Alder (Alnus incana), White Willow (Salix alba), Black Poplar (Populus nigra); on the slopes, Silver Birch (Betula pendula) and Hornbeam (Ostrya carpinifolia).


Extraction Activity of "Piera Dolza": Easily Workable Rock

The extraction activity of sandstone, locally known as "Piera Dolza" for its ease of work, began in 1500 and ended in 1950. From here, stonemasons obtained elements useful in local architecture, such as door and window jambs, cornerstones, steps, and decorative elements like the spires of the Fregona bell tower and parts of buildings in Vittorio Veneto. The stone columns in the caves are a structural support left intentionally by the quarrymen to prevent the vault from collapsing. The sandstone layers of the Fregona Coast in which the cavities are excavated are naturally inclined at about 45°.

The stonemasons used few tools (hammer, mallet, points, wedges, etc.) and skillfully followed the stratification. The sand remaining from sandstone processing, called "saldame," was used to polish copper (which oxidized easily) kitchen tools. From compact conglomerate benches, they also extracted grindstones for milling wheat.

Ancient Mill

The "Mill of the Caldiere" is documented from the early 15th century, but its construction can reasonably be anticipated at least two centuries earlier. The extremely delocalized location from the ancient vicus of Fregona can be explained for two reasons: one political, as the mill was near the overlying castle of the powerful comital family of da Camino, which collected fees for grain milling; the other, geographical (probably the most important), due to the presence of the building downstream of the Caglieron stream gorge. The watercourse, affected by a significant drop along the gorge's path, between jumps, waterfalls, and potholes, provided, through a millrace, or an artificial canal still existing, hydraulic energy to the undershot wheel (a wheel characterized by consecutive buckets that, filling with water, cause its movement). Since the 1970s, the building's intended use has changed to a public bar and restaurant, currently open.

Caglieron Mill

Similar to the previous one, the Caglieron Mill exploited the water of the stream; dating back to the late 1800s, it has been reconstructed and will soon be completed with the millstone, allowing for educational purposes.

Breda Washhouse

Halfway between the ancient mill and the stonemason's village, you come across, on the left, a viewpoint from which you can observe two pools that locals used for washing clothes.

Stonemason's Village

The Stonemason's Village is a restoration of a rural building, where you can observe door jambs made of "piera dolza" and other elements that teach us about life in the park in the recent past.

The Stonemason's Village and the adjacent land provide a good example of how nature reclaims spaces taken from humans and, subsequently, abandoned. The meadow is now covered by a dense blackberry bush, a precursor to the forest. With disturbances ceased, in the space of a few decades or centuries, natural vegetation will return. In the meantime, the intricate thicket will host and shelter numerous animals. Even the dry stone wall, made with local stone, between the house and the front building, harbors a small community of plants.

San Lucio Cave

The San Lucio Cave, also known as the Cheese Cave, due to its natural characteristics and the microclimate it preserves, takes care of the cheese and influences its maturation, enriching it with flavors and scents of bygone times, almost transforming it into one of the sandstone blocks that were once extracted from it and used to decorate door jambs and capitals. Currently, it is a protected environment, with numerous wooden shelves for aging the cheese.

Santa Barbara Cave Mushroom Farm

Due to the favorable conditions of temperature and humidity in the cave environment, almost constant throughout the year, the Santa Barbara Cave was used as a mushroom farm in the past. The germination substrate consisted of hay bales on which Pleurotus mushrooms were cultivated.

Fregona Bell Tower

Significant for the use of stone is the construction of the Fregona Bell Tower, which began in 1880 and was completed in 1909. The entire local population participated in the construction work, carried out on holidays when the residents were not busy in the fields. The bell tower, in neo-Gothic style, is particularly tall and with a powerful bulk, although softened by daring spires. The 12-meter spire that was supposed to complete it was never finished. The bell tower is clearly visible from the park, and during certain events, it is possible to visit its interior. The structure is adorned with various sculptures, including dragon and lion heads and exquisite acanthus leaves: a testament to the industriousness and remarkable skill of the stonemasons of Breda, who, from the "soft" stone of Caglieron (light beige) and the "blue" stone from the Masarè quarries, knew how to extract the materials for the construction of this bell tower that unmistakably marks the panorama at the foot of the Cansiglio.