15°23′48″E
≈ 516 m
One stretch of valley · four discoveries
Below
Burg
Hartenstein
In the valley of the Kleine Krems, carved deep into the gneiss of the Waldviertel, four things sit close together: ice-age caves, a geological trail, the meeting of two rivers — and, on the slopes above the castle, one of the best bouldering areas in eastern Austria.
Four domains, one place: wherever you arrive — the other three discoveries are just a little further down.
The same geology, told from four angles.
Below the ruined castle of Hartenstein, perched on a block of rock, everything lies close together: the marble band with its caves, the folded gneisses of the geological trail, the “Zwickl” where the Große and Kleine Krems become the Krems — and above, in the woods over the castle, the shady bouldering blocks.
In a single day you can walk through a hundred thousand years of settlement, through the mountain-building of the Waldviertel and across grippy rock — on foot, only a few minutes apart.
The Caves of the Kremstal
Right below the castle, in a pale band of marble in the castle rock, opens the Gudenus Cave — a roughly 30-metre through-cave a good eight metres above the Kleine Krems and one of the oldest settlement sites in Central Europe. Finds reach back some 70,000 years; from a later period (Magdalenian) come the most famous pieces: a bone flute — the oldest musical instrument in Austria — and an eagle bone engraved with a reindeer’s head, both now in the Natural History Museum in Vienna.
The rock band continues, and with it a whole series of caves where researchers recovered ice-age bone finds:
The valley path is easy — but the higher caves (Schusterlucke, Teufelskirche) can only be reached via the partly secured Vettersteig with ladders. Good footwear, sure-footedness and a head for heights are recommended.
Geological Trail
Founded by the geologist Prof. Dr. Alexander Tollmann, the trail runs for a good two shady kilometres with little change in elevation along the rock faces of the Hartenstein valley section, passing the Gudenus Cave. Nine panels explain the rock formations in detail — a companion booklet is available at the Albrechtsberg municipal office.
What you learn to read along the way:
The starting point is the Maigenmühle, on the road between Weinzierl am Walde and Albrechtsberg. Follow the waymark black–GEO–white.
The Zwickl
Near Albrechtsberg, in the narrow, wildly romantic river valley, the Große meets the Kleine Krems. “Am Zwickl” is what this spot is called — from here on both are simply “the Krems”, flowing together towards the Danube. It is a quiet, almost enchanted place: in a broad arc the water rushes around the castle rock, with dark wooded slopes rising steeply.
It is not for nothing that this stretch is nicknamed the “Grand Canyon of the Waldviertel”. From the Zwickl it is only a few minutes upstream to the castle, the Gudenus Cave and the trail.
The valley path along the Krems to the Zwickl is comfortable and almost level — it can be walked with a stroller without any problem. (The higher-lying caves are the exception.)
The Hohenstein power station
Right at the Zwickl, just after the confluence, a historic small hydroelectric station stands above the foaming water — so playfully built and beautifully restored that it resembles a little water castle. At the valley fork a weir dams the water into a head pond.
Once built to turn the water power of the Krems into electricity, the “Kraftwerk Hohenstein” still defines the valley basin today. Opposite rises the Wotansfelsen — power station, rock and confluence make one of the most striking scenes in the whole Kremstal.
Bouldering above Hartenstein
The bouldering area above the castle is regarded among climbers as one of the best in eastern Austria — some topos even call it the best in Lower Austria. The dark, grippy gneiss and good landing make it a classic; the blocks lie hidden in the beech woods across several sectors — often you have them entirely to yourself.
The hardest boulders wait in a cave a little further down the path. Because the area faces south-east, it can even be climbed in winter sun. Approach via the Teufelsrast or from Purkersdorf — watch the markings, or the start is easy to miss.
Bring a crash pad; grades from easy to about 7b/7b+. Please treat rock, moss and forest with care — the area lives on its quiet.
Right on the Lebensweg
This valley floor is also a section of the “Lebensweg” (Path of Life) — a roughly 260 km long-distance trail through the southern Waldviertel whose 13 stages each symbolise a phase of human life. It links two waymarked routes, the Kremstalweg no. 625 and the Ysper-Weitental circular trail no. 22, and is deliberately walked in one direction only.
So those who hike here travel not only through geology, but symbolically through life as well.
Integration / settling down
Through the “Grand Canyon of the Waldviertel”
Down from Els to the Kleine Krems, past Burg Hartenstein and the Gudenus Cave to the Zwickl — where the Kleine and Große Krems become the Krems — and onward along the Große Krems. The geological trail and the off-path caves lie directly along the way.
- Trail
- Lebensweg / Kremstalweg no. 625
- Season
- April to October
- Direction
- waymarked one way only
Frequently asked
Is the path to the Zwickl suitable for a stroller?
Yes. The valley path along the Krems to the Zwickl is level and easy and can be walked with a stroller without any problem. The higher-lying caves are the exception.
Do you need special equipment for the caves?
The valley path is easy. The Schusterlucke and Teufelskirche caves, however, can only be reached via the partly secured Vettersteig with ladders — sturdy footwear, sure-footedness and a head for heights are recommended.
How hard is the bouldering above Hartenstein?
Grades range from easy to about 7b/7b+ on dark, grippy gneiss. The south-east facing area can even be climbed in winter sun; a crash pad is recommended. Tour descriptions are available at the Alpine Club (see the bouldering section).
Where is the starting point and when is the best time?
The starting point is the Maigenmühle, about 15 km west of Krems an der Donau. The valley is part of the Lebensweg (stage 7) / Kremstalweg no. 625; recommended season April to October.
All in one place
Map detail Burg Hartenstein · little Kremstal valley
Note: markers other than castle/Gudenus Cave are approximate — exact coordinates can be adjusted in the script below (array POINTS).
Getting there & location
The little Kremstal valley lies about 15 km west of Krems an der Donau, within the municipalities of Weinzierl am Walde and Albrechtsberg an der großen Krems.
The starting point is the Maigenmühle, on the road between Weinzierl am Walde and Albrechtsberg; from there you follow the forest road along the Kleine Krems. The valley path to the Zwickl is level and comfortable (stroller-friendly); the higher caves and the bouldering area require sturdy footwear and sure-footedness. For bouldering, park near the bridge by the castle or, for a shorter approach, in Purkersdorf.
As of 2024: the footbridge over the Kleine Krems to the Gudenus Cave has been removed due to disrepair. The castle itself is privately owned and can only be seen from outside. Please respect the paths and nature.
Where to stay
If you want to stay longer: the Waldviertler Ferienhof in Purkersdorf/Albrechtsberg is a historic four-sided farmhouse — an ideal base for caves, hiking and bouldering.
waldviertlerferienhof.at →