It has been visited since 1906 and offers 250 meters of galleries to discover on an underground path, punctuated by walkways. The geological interest of the Seythenex cave is immense. You can observe the different calcite strata there. The typical formation of its hoses, called "keyhole" testifies to the way in which the waters have shaped these underground galleries, first digging circular conduits and then eroding the rock downwards, when the water no longer fills fully galleries. The visit to the cave is guided, and lasts approximately 35 minutes.
Another natural gem to discover on the site is the Seythenex waterfall. The fall is that of the waters of the Saint Ruph, a torrent that rises at the Col d'Orgeval to reach Lake Annecy. With its 45 meters in height, it offers a striking spectacle. Below, the tumultuous waters of the river form sublime giant pots before continuing their descent to the lake. A guided tour of the site is offered, as well as its overflight by zip line: an unforgettable experience in an exceptional natural site, 40 meters high and 150 meters long.
The site of the Seythenex cave and waterfall finally has a projection room which broadcasts a documentary film on the daily life of the inhabitants of the region during the past centuries. You can also admire a model that reproduces the landscape of the village with old houses, workshops of artisans, water mills on the Saint-Ruph and the millstone that they allowed to operate.
The site opens its doors to visitors from mid-April to mid-September. On the terrace you will find a bar and a snack service, ideal for relaxing with a panoramic view of the Aravis range. There is also a gift shop, and picnic tables are available. The cave and the waterfall are located at 576 route des Grottes in Seythenex, 15 minutes (for 11 km) from the Ideal campsite. The individual price for guided tours is 8 euros for adults and 6 euros for children from 4 to 12 years old. Entrance is free for children under 4. In July and August, the site opens daily from 9:30 a.m. to 5:30 p.m. (departure time of the last visit). From April to June and September, it can also be visited every day, but the last departure is at 5:00 p.m. For groups, reservations should be made in advance.