Grotte di Oliero

Grotte di Oliero: nature at its finest

Hey guys, welcome back to the hiking section! Long time no see—blame it on the weather, I swear!

Today, I'm excited to share the story of our last hike to Grotte di Oliero, which was honestly one of the best experiences we've had so far (in my humble and honest opinion ofc). "Who's Oliero?" you ask. Keep reading—it might even help with your attention span!

How in the world do you reach those caves?

Easy answer—though our journey wasn't quite as straightforward as planned! As always, let's start with our experience: we traveled to the nearest train station in Carpanè-Valstagna. Usually, you'd just walk for about 20 minutes to reach the park, and we were mentally prepared for that leisurely stroll but... surprise! The pedestrian bridge crossing the river was (and still is) closed for maintenance work.

Now what?? We thought our adventure had ended before it even began, when a guy approached us and mentioned a shuttle bus service. Plot twist—he was actually the bus driver himself and, moved by the *obvious* sadness and desperation in our eyes, he made an exception to his scheduled route and drove us directly to the entrance. What a hero! Talk about starting our day with a stroke of good luck.

Navetta timetable

So, if you need to cross the bridge near the Carpanè-Valstagna train station to reach Valstagna (or vice versa), be aware that maintenance work is ongoing. You'll need to take a free shuttle bus to reach the caves, the train station, or Valstagna (timetable in photo). This won't affect your wallet as it's a complimentary service to compensate for the inconvenience, but definitely keep it in mind when planning your visit.

Btw, here you have all the possibile routes and options:

• ON FOOT: Once the works are done (maybe around April/May), from the Carpanè-Valstagna station, just cross road SS 47 and head south. At the traffic light, turn right and follow the signs to "Grotte di Oliero." Cross the bridge and turn left, then simply follow the path along the river for about 1.5km until you reach the park entrance (you'll end up right in front of it). The riverside walk itself is absolutely gorgeous and well signalized.

• BY CAR: If you're taking the highway, you can conveniently exit at "Casello di Bassano del Grappa Est - Rosà" and follow SS 47 Valsugana until you reach Campolongo sul Brenta, where you'll turn left onto the bridge. After crossing, turn right and follow the signs to "Grotte di Oliero." 

If you're coming from Trento, turn right at the traffic light in Carpanè-San Nazario onto Valsugana, cross the bridge, and turn left, following directions for 1.5km. 

There are several parking spots available, but be mindful that during summer and holidays, they fill up quickly. Early birds catch the best spots!

• BY BUS: If you're near Bassano del Grappa, head to the bus station and take bus n°49. The nearest stops are either "Oliero di Sopra" or "Oliero di Sotto," both less than 100m from the park entrance. Super convenient!

Time to go in

Welcome board

Once you finally reach this dreamy place, you'll need to spend a few euros for entrance. I know, I know—but trust me, it's completely worth every cent! Children, disabled people and students qualify for discounts, so check what's best for you on their website. Our visit started with a delightful 2 euro discount because we're university students (up to 25 yo though), so we paid just 10 euro each to visit the park, the museums and to have the guided tour inside the cave—not bad at all!

We also arrived at the entrance just one minute before the official opening time (if you ever invite us somewhere, you know we'll show up punctually). Thanks to our early arrival, the area was blissfully quiet and tranquil, giving us time to chat with the super friendly staff at the reception. They went the extra mile by asking the guides to conduct the tour in both English and Italian for our group—how thoughtful! It's these little personal touches that make a trip truly special.

Us posing in Covol dei Assassini

Now let's start our hike! 

• Museums and Covol dei Assassini

We then went straight to the speleology and karst museum, and paper mills museum, where you can find various QR codes to scan and listen to the audio-guide (provided both in English and Italian). When we got out, we found ourselves on a double-way path and decided to go to the right first, towards "Covol dei Assassini" (Cave of the Assassins), still connected to Oliero Cave. Alright, alright, I'm gonna tell you who Oliero is now: with its 300m in length, it is the shortest river in Europe, born under the Asiago massif and finishing its run straight into the much bigger and longer Brenta river. Tiny river, big personality.

• Covol dee Soree

Glimpse of Covol dee Soree

Following a narrow path lined with beautiful vegetation and fascinating rock formations, accompanied by some lizards and a couple of butterflies, we made our way to "Covol dee Soree" (Cave of the Sisters). Though completely sealed by a collapse of the cave's walls, it's still a wonderful site - and it has comfortable benches if you want to have a snack under its cool shade. Perfect spot for a quick rest! 

• 
  Parolini's Cave (Covol dei Siori) 

The trail then meandered alongside Oliero's crystal-clear stream, leading us near "Covol dei Veci" (Cave of the Elders). En route, we encountered a couple of friendly geese, who peacefully started following us (they probably hoped for some crumbs - please do not feed bread to them, it will bloat them up). We stayed there for a bit, took some photos and videos, looked at the fascinating rocks and splashed a little in the water... well, our hands only, as the water was refreshingly cold!

Filled with joy and excitement, we made our way to the crown jewel of the park: Parolini's Cave (or Grotta dei Siori - Gentlemen's cave). We were provided with a hair net and a helmet (safety first, the cave's ceiling is very low in the first part), accommodated ourselves on the boat and started the tour with our two wonderful guides. We glided on top of one of Oliero's springs as the temperature dropped noticeably (12°C / 53.6°F all year-round - remember to bring a jacket). Our guide illuminated the chamber and revealed the cave's spectacular formations—stalactites and stalagmites that had formed drop by painstaking drop over thousands of years. We saw three main stalactite formations:

1. "Corn stalactite", which is the shape that most stalactites have, with one base and one tip and that is because water drops run parallel to each other until they meet in one single point. This one in particular is also called an angel because the surrounding little stalactites look like a pair of beautiful wings. (ITA: "stalattite a pannocchia / l'angelo") It's absolutely stunning!

2. "Elephant ear", a name given because of its width and how thin it is; this drape-like shape is formed by the path that water drops follow, which is on the stalactite's side rather than going from base to tip. Another name given to this peculiar formation is "the mother-in-law's tongue" (ITA: "orecchio d'elefante / lingua di suocera")... Listen, I'm not the one making up the names!

3. "Cluster/family of stalactites", called like that because they share the same base but each is on its own, as water drops followed different directions over time. Nature's creativity at its finest!

up: baby stalagmite
down: flowstone

We also witnessed a baby stalagmite -so maybe we could go back in a couple of million years to see her graduation- and a beautiful example of flowstone, formed by water running down the cave's walls, like stalactites/stalagmites but on a wall.

⚠REMEMBER⚠: do NOT TOUCH the stalactites or stalagmites. The oils from the skin on our hands can stop their growth because oil is not soluble in water, so the latter just runs away, unable to deposit calcium carbonate (CaCO₃ - limestone); also, you have no reason at all to touch them (trust me, it'd probably feel like...rock). If you're craving to touch some limestone, just go scrape some of that limescale lingering around your shower!

Lunch time & Covol dei Veci

Emerging from the cave's twilight, we got hungry and it was in fact noon, perfect timing- outside the cave there is a wonderful picnic area with benches, lots of chairs and bathrooms (keep in mind that the locks are momentarily not working). We had lunch with that same couple of geese, who got out of the water looking for something to eat as well. They're most probably used to visitors and they were very friendly and chill, they just wanted some food - we tried giving them some fruit and salad but all they wanted was bread... spoiled little creatures.

After lunch, we went back to the crossroads at the beginning and took the path on the left, which took us across a charming bridge spanning the river. We paused midway, leaning against the railings to watch the emerald waters flowing out of the springs. The bridge offered a spectacular vantage point of the entire valley, with the rugged Dolomite foothills creating a dramatic backdrop against the blue sky. Absolutely breathtaking! Just beyond the bridge, up on a little hill, there was a massive cherry tree in full bloom, from which some petals where floating away in the wind. We couldn't resist taking another break beneath its canopy, lying on our backs to gaze up through the flowers; it really felt magical and quiet.

Covol dei Veci

We would've loved to stay there longer but we had one last cave to explore: Covol dei Veci. We had a peek of the cave on the other side and it was time to get closer and keep going with the exploration. This partially accessible cave, is the second spring of the Oliero river and it is not accessible neither on foot nor on boat, as the entrance is very narrow and only experts cave divers can go in because it is obviously filled with water.  

Valstagna and the infamous bridge
over Brenta river

In the afternoon, we reluctantly made our way back, but only after staying another while under the cherry tree (c'mon it was irresistible). At the entrance, we said goodbye to the staff who also helped us understanding the shuttle bus situation to go back to the station and started our walk to Valstagna along Brenta river. 

Finally, we reached the bus stop and, as we waited for our transportation back to the train station, we shared our favorite moments from the day—the spectacle of the caves, the refreshing waters, the blooming cherry tree, and the unexpected wildlife encounters. The free shuttle arrived right on schedule and we caught the train just on time, the perfect end to a perfect day of adventure :)

I hope you're ready to read the interesting part: how did these caves form and who discovered them??

The Remondini family, printers from Padua, established a paper mill in Bassano in the mid-1700s powered by the pristine waters of the Oliero—one of the world's shortest rivers, ideal for paper production. From the 16th century, various businesses operated along the Oliero stream using its water power (the current ticket office and museum building was once their paper mill).

Alberto Parolini (1788-1867)

After the Napoleonic wars, Francesco Parolini purchased the declining mill and his son Alberto, a passionate naturalist, who was the first to explore the Oliero basin, discovered the cave entrances, and opened them to the public in 1822.

Alberto Parolini was an accomplished botanist, mineralogist, and explorer who traveled extensively throughout Europe, Greece, and Asia. He named the caves we still visit today: Parolini Cave (Covol dei Siori), Cecilia di Baone Cave (Covol dei Veci), and Sisters Cave (Covol dee Soree) in honor of his two daughters. His impressive natural history collections became treasured items in the local museum, earning him both Italian and international recognition. 

What created the caves?

The Grotte di Oliero are the result of nature's patient artistry spanning millions of years; It all starts with rainwater playing a clever chemistry trick: as rain falls through our atmosphere, it picks up carbon dioxide (CO2) and transforms into a mild natural acid. This slightly acidic rainwater then seeps through tiny cracks in the limestone (CaCo3) or dolostone (CaMg(Co3)) of the Asiago Plateau and—very slowly but surely—dissolves the rock to carve out these spectacular underground chambers we get to explore today. Imagine the plateau as a gigantic natural sponge, with water doing that same thing over countless millennia. This phenomenon is known as KARST. These caves are the grand finale of a grand underground water journey: all the rainfall that filters through the massive Asiago Plateau (about 500 km2) eventually emerges right here at these springs, producing up 8 million cubic meters of water per day. 

Originally, the area featured more than two springs, but over time, two of them gradually ceased flowing. One even closed completely when its cave walls collapsed without the running water to maintain the passage. These lost springs are the "Covol dei Assassini" and "Covol dee Soree". The former remains partially accessible and presents an interesting challenge for speleologists and cave explorers, while the latter has become completely sealed off and inaccessible.

Rock Composition

The mountain group consists of sedimentary rocks deposited in a marine environment between 223 and 35 million years ago. The entire highland rests on a dolomite foundation, while the upper layers are formed by gray limestone (rich in fossils), often accompanied by biancone, ammonitic red rock, or red scaglia in different areas.

The geomorphology of the entire region is significantly influenced by karst dissolution, which makes surface water quite rare while underground cavities are numerous (many explored, some deeper than a thousand meters, like the Malga Fossetta abyss).

The area is rich in fossils: in Kaberlaba, the first plesiosaur skeleton found in Italy was discovered and in various parts of the plateau, the Ammonitic Red rock shows a stratified appearance. These tabular formations (like those on the Melette) are due to the disintegrating action of cold on rocks (frost weathering) occurring in cold environments. The frost weathering, which externally shatters the softer rock, highlights the different composition of the limestone itself (stratification).

The Mysterious Proteus – A living fossil

One of the most remarkable inhabitants of the Oliero cave system is the proteus (Proteus anguinus), also known as the "human fish" or "olm." This fascinating amphibian is perfectly adapted to life in complete darkness and is one of the most iconic cave-dwelling animals in the world.

The proteus has several extraordinary characteristics:

• It's completely blind, having evolved in darkness where eyes serve no purpose
• Its skin is a pale, pinkish-white color due to lack of pigmentation
• It can grow up to 30 cm (12 inches) long
• It has external gills that remain throughout its life, unlike most amphibians
• It can live for an extraordinary 100+ years
• It can survive without food for up to a decade by slowing its metabolism

The presence of the proteus in the Grotte di Oliero is a testament to the pristine quality of the water and the unique ecosystem that exists within these caves. These rare creatures are protected by law and seeing one during your visit would be an incredibly special experience, though they're often kept in special observation tanks to protect their fragile habitat.

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These caves are still forming today! Each drop of water that falls is still carrying minerals, still building those formations, still sculpting the cave—just very slowly at only a few millimeters per century. When you visit, you're witnessing active geological processes that have been running continuously since before humans even existed. 

I hope you liked this little "online journey" of the park, we truly recommend it - try avoiding summer, it usually gets crowded :) 

-A.