As a tomb went out of use, it was surrounded by a ring of standing stones.
In the 1870s, the stones were interpreted as druids' temples and the landowner planted a grove of trees enclosing the three largest monuments.
Some of the trees are rowans, thought to protect against ghosts, witches and other evils. Coincidence?
The North-east passage grave is carefully aligned on the midwinter solstice. Normally the chamber would be dark, but on this shortest day of the year, it was illuminated by the setting sun.