It's a rather nice ornate Baroque building, dating from 1652, replacing a structure built in 1606 near a much more ancient holy well (which supposedly confers good fortune in romance to those who drink from it). A group of concerned local citizens (or, in ancient terms, a confraternity) is responsible for keeping it all going, with support from the Government of Flanders.
The chapel has regular weekly prayer, but Mass is celebrated there only on a few occasions in the year - a candle-lit celebration on 2 February; an open-air Mass and procession on 1 May; another open-air Mass and procession on 15 August; the feast of St Hubert on 3 November, at which animals are ritually blessed; and the Midnight Mass for Christmas.
The informed observer will note that three of those dates are pretty close to the ancient Celtic festivals of Imbolc/St Brigid's Day, Beltane and Samhain, and 15 August is only two weeks displaced from Lúnasa. My sneaking suspicion is that the site of our chapel has been a venue for seasonal religious celebration for a lot longer than Christianity has been in these parts.
Christmas is of course the interloper, historically speaking, but possibly the most popular of the five. Tonight the chapel was crowded out - probably many of the congregation, like me, had not been to an act of worship for a very long time. For an hour, I put aside my reservations about organised religion and enjoyed being part of a community tradition in my adopted country.
A choir of three women led the singing. Here they are with the Dutch translation of Stille Nacht / Silent Night (I was in the balcony, having arrived late):
And then I walked home again through the woods, flooded by moonlight to the point that I didn't need to use up my phone battery to light the way.
Merry Christmas, all.