Grotta del Caglieron, Cave system in Fregona, Italy.

Grotta del Caglieron is a cave system in Fregona featuring multiple underground levels with limestone walls, natural waterfalls, and pools formed by flowing water. Wooden pathways guide visitors through the different chambers and passages.

Quarrying of sandstone, called 'piera dolza' locally, began in the 16th century. Workers cut inclined columns to support the vault, leaving artificial cavities above the Caglieron stream. The stone supplied jambs and lintels for houses in Vittorio Veneto and nearby.

Local dialect calls the sandstone 'piera dolza', soft stone. Blocks cut here became jambs and lintels in houses of Vittorio Veneto and the surrounding area, so the quarry's stone can still be read on the doorways of the town nearby.

The visit follows an equipped route laid out along the bottom of the gorge, where the Caglieron stream flows between the quarried cavities. The path passes close to the waterfalls and their pools, so surfaces are wet and slippery; wear shoes with grip. The inclined pillars cut to hold up the vault stand beside the walkway.

The cave still displays marks and cuts from the time of sandstone quarrying, etched into the rock surfaces by workers. These archaeological traces reveal how extraction was done in earlier centuries.