I chanced to look up at a wall in the back corridor of my house, and saw evidence of a visitor while I had been away for several months.
The first photo shows what I saw, from a safe distance.
This warranted closer inspection, so armed with a step-stool and camera, I zoomed in for this shot.
It was the nest of a mud-dauber wasp, and 2 of the 3 chambers were open and empty. I’ve often seen them outside, this was my first experience with them inside my house.
They’re quite fascinating insects, read about them in this link. They are welcome to share my life, as they do get rid of a few spiders for me!