Grottes des 1001 Nuits

Grottes de Hotton

Useful Information

Location: Chemin du Speleo Club, 1, 6990 Hotton sur Ourthe.
Near Hotton.
(50.259115, 5.456038)
Open: Carnival School Holdiays daily 11, 12:30, 14, 15:30.
Easter to JUN daily 10-17.
JUL to AUG daily 10-18.
SEP to All Saints' Day daily 10-17.
Christmas School Holdiays daily 11, 12:30, 14, 15:30.
Fee: Adults EUR 12, Children (3-11) EUR 9, Children (0-2) free.
Groups (20+): Adults EUR 10, Children (3-11) EUR 7.
Classification: SpeleologyKarst cave
Light: LightIncandescent Electric Light System
Dimension: T=12 °C, L=5,000 m, VR=71 m, A=248 m asl.
Guided tours: D=60 min, L=300 m, VR=65 m, St=580. Nederlands - Dutch English Français - French
Photography: allowed
Accessibility: no
Bibliography: J.F. Cadorin, D. Jongmans, A. Plumier, T. Camelbeeck, S. Delaby, Y. Quinif (2001): Modelling of speleothems failure in the Hotton cave (Belgium). Is the failure earthquake induced?, Netherlands Journal of Geosciences / Geologie en Mijnbouw 80 (3-4): 315-321 (2001). pdf
Address: Grottes des 1001 Nuits S.A., Chemin du Speleo Club 1, 6990 Hotton sur Ourthe, Tel: +32-84-46-60-46. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1958 cave discovered during quarrying.
21-APR-1962 cave opened to the public by the owner of the neighbouring meadow.
1964 cave operated by the company Grotte des 1001 Nuit.
1994 cave purchased by the company Grotte des 1001 Nuit.


This cave has two names, the name Grottes de Hotton is easy to understand, as they are located near the village Hotton. The favoured name Grottes des 1001 Nuits is a bit strange, as nothing in or around the cave resembles the stories of 1001 night. This name seems to be a sort of advertising stunt. They explain the name with the caves being the most beautiful caves of Belgium.

The cave was discovered during quarry works in 1958, and exploring started by the cavers. Like often in such cases, the interests of the quarry owner and the protection of the cave collided, and there were some quarrels. The owner of the quarry was afraid that his quarrying would be disrupted, and so he made it inaccessible in 1959. Before he closed the cave, the cavers had been able to survey a small portion of the uppermost level of the cave, and they knew that there were passages quite close to the surface, outside the property of the quarry owner. In 1961, they broke into the cave and started to dig from the highest room towards the surface. Finally, they reached the surface in a meadow nearby, whose owner was quite happy and immediately opened the cave as a show cave. A company named Grotte des 1001 Nuit was founded which became the tenant and operator of the caves in 1964. So it seems this weird name was the idea of the cave owner, probably he thought this would bring more visitors to the cave. The company became the sole owner in 1994.

The tour starts at the surface and goes down several levels of the cave to the biggest chamber of the cave, 65 m below the surface. There is a balcony, overlooking a huge hall, which is called salle du gouffre (chamber of the chasm) and is 35 m high, 200 m long, and 10 m wide. This chamber is also called galerie du Spéléo Club de Belgique (gallery of the Speleo Club of Belgium). It is said to be the largest gallery in Belgium. The cave has deeper parts and the lowest level of the cave is an active river cave. From here the trail leads up staircases for 30 m, and then there is an elevator for the 35 m back to the surface.

The cave is quite interesting, as the layers in the area are nearly vertical. They were tilted by the tectonic forces, which formed the Ardennes. So the cave developed along the vertical layers, and most of the passages have a rectangular profile. One side of the passage is the upside of a layer, the opposite side is the downside of a layer. The roof shows numerous cut through layers. The passages follow the layers.

The surfaces show interesting erosive forms, like Karren. Some layers are harder, some are softer. At the floor and ceiling the softer layers are more easily eroded.

The cave has only small speleothems, a few soda straws. The stalactites grow with about 8 mm in one hundred years, which is far below average in caves with this rather high temperature.