During the school Christmas break we take the opportunity to go and visit places. Last week, my girlfriend and I spent a few days in a hotel in the south of the country, from which we visited various cities and towns. The stop for our first day was the town of Valkenburg, in the far south of the Diocese of Roermond (and therefore of the country as a whole).
There, to my surprise, a visit to a Christmas market in a former mine complex revealed a very special former church. During the reign of Napoleon, the Netherlands was annexed to the French Empire, and the Catholic priests were required to make an oath of allegiance to that empire and its ruler. Many refused to do so, and were either imprisoned or exiled for that. Many priests had to offer their Masses in secret, and the priests of Valkenburg and surroundings chose what is now called the ‘Velvet cave’ to use for a makeshift chapel. Baptismal fonts, altars and other requirements were cut out of the soft chalk of the mine and carefully decorated. The masonry and artwork is still preserved, as are memorials to priests who were imprisoned and exiled.
In later decades, more artwork and graffiti appeared, not least from American soldiers who used the caves to fight the German oppressors during the later stages of World War 2.
A photo impression: