Grottes de la Balme, Show cave in La Balme-les-Grottes, France.

Grottes de la Balme are limestone caves extending through the rock with multiple chambers, passages, and underground water features shaped by flowing water over time. The cave system reveals different levels and formations that showcase how water slowly carved through stone.

The cave was occupied in prehistoric times; late Bronze Age tombs with cremation urns and animal offerings were found in rock crevices. In 1516 Francis I came with his mother Louise of Savoy to pray in the chapel after Marignan, and is said to have led the first exploration of the underground lake. The site has been open to the public since 1807.

The name is a pleonasm: "balme" (or "baume", barma in Francoprovençal) already means a natural cavity in the Alps. The site is listed among the old seven wonders of the Dauphiné and takes part in the European Heritage Days. A fresco of Francis I, painted in 1882 by Théodore Levigne, stands at the cave exit.

The cave stays cool year-round, so bringing a light jacket is wise for comfort during your visit. Sturdy shoes help on the pathways, and guided tours take visitors through the different chambers and passages at regular intervals.

The cave shelters 23 bat species, alongside tawny owls and rock swallows. The name "balme" itself is a pleonasm: in the Alpine and pre-Alpine regions it already means a natural cavity, from barma in Francoprovençal and baume in Provençal.