Grotte et cascade de Seythenex, Natural cave and waterfall in Faverges-Seythenex, France.

Grotte et cascade de Seythenex is a cave system carved through limestone where water has shaped underground passages and chambers over millennia. A waterfall drops roughly 40 meters near the entrance, feeding a stream that flows through the passages below.

Water flowing through limestone created the cave system over thousands of years, gradually dissolving the rock and carving out passages. Local explorers later discovered and opened the site, making it accessible to visitors.

The cave's name, Seythenex, comes from the hamlet where it opens, in the commune of Faverges-Seythenex. Guided visits explain how the stream carved the galleries and the 40-metre waterfall, and the site is also used for adventure activities such as canyoning and via ferrata nearby.

Wear sturdy shoes as the cave floor can be uneven and slippery in places. The tour involves some climbing and navigating through tight passages, but routes are generally manageable for visitors of average fitness.

The zipline is a via ferrata crossing above the 40-metre waterfall, letting visitors hang over the drop rather than view it from below. It is a separate activity from the guided cave tour, so the two can be booked independently.