Caves Sainte-Anne, Natural cave system in Tilff, Belgium

Caves Sainte-Anne opens in a wooded slope above the N633 between Tilff and Méry, in Esneux. Its entrance porch is 4 to 5 m high, 10 m wide and about 15 m deep, with old concretions visible in the rock. The cave runs about 1,542 m with a 35 m rise and has four stacked levels cut as the Ourthe valley terraces formed; the lower level still carries an underground river.

The cave was discovered in 1837 when quarry workers broke through into the underground system and recognized its scientific value. Since then it has been developed for public access and continues to attract researchers interested in Belgian geology.

The name Sainte-Anne refers to Saint Anne, mother of the Virgin Mary, a common dedication in the Liège region. Since 1991 the entrance has been locked by the Union Belge de Spéléologie, which manages the key. The cave is declared a "grotte-école" and is regularly used by youth groups learning caving under experienced guides.

You will need a special key to enter the cave and should wear sturdy shoes and suitable clothing since the temperature stays around 12 degrees Celsius year-round. It is wise to check access conditions before your visit to understand what to expect underground.

In 1962 Étienne Lemaire, founder of the Groupe d'Activités Spéléologiques, reached the upper network by squeezing through a narrow, water-fed passage known as the "Boîte aux Lettres". Beyond it lies the Réseau Lemaire and a hanging lake about ten metres deep, ringed by gours. The entrance has been locked since 1991, with the key managed by the Union Belge de Spéléologie.