Looking south-east across the mile or so of sand at Traeth Lligwy. Sadly, it doesn't look at its best under a grey sky. Note the mud casts, which suggest the presence of sand-dwelling animals, which in turn implies the presence of mud and organic remains in the sand.
This is one of two Quadrant Shelters for the WW2 Lligwy Bombing Range.
It would have held a Quadrant Sight Unit used to visually plot the bearing of the impact of a practice bomb and the result used in conjunction with the reading from the other quadrant to plot the point of impact by triangulation.