The most mysterious of the Boyne Passage Tombs also the least visited and reconstructed.
A vertical zig-zag pattern on the rear wall of the main chamber.
The entrance to the south chamber is orientated to the setting sun around the time of the winter solstice, many observations have been made that confirm the sunlight penetrates the passage and chamber, reflecting off the back wall of the main chamber into a side chamber, illuminating some intriguing carvings, shown below.
The passage of the south chamber, looking out from inside. The electrical fittings do not work.