The H.H. Lambertus and Genoveva Church is an old church on a hill in Holset. At the foot of the church hill is the Lambertus source and next to it a Lourdes cave from the end of the 19th century.
When building this cave, a large collection of fossils was used to decorate the wall. The many hundreds of fossils, including a large number of pieces of silicified wood, have been incorporated in every possible place. The collection was probably brought together by the pastor.
The cave is hidden in a long, high wall of natural stones. There is a statue of Mary in the cave. On the ground is a statue of a kneeling Bernadette. The cave is closed by a long, wrought iron decorative gate.
Holset had great cross-border appeal at the end of the 19th century. In 1884, for example, 18,000 pilgrims, including many from Aachen and the surrounding area.
Although the Lourdes Grotto was restored in the 1990s, the Lourdes devotion itself did not revive and has been concentrated within the municipality for some time on the Lourdes Grotto in Vaals.
Lambertus' source has also been forgotten. The pool at the source has become a kind of 'eco-pilgrimage site', because it is a special reserve for the midwife toad ('kluksje').