Inside the passage of Cairn T (The Hag's Cairn) at Slieve na Calliagh, Loughcrew, Co. Meath. The interior of Cairn T is richly adorned with megalithic art, some of which resembles rock art. Some stones in the passage are covered with cup marks (the holes that you see on the stone on the left). The sun shines into this passage at the equinoxes and illuminates a stone deep in the interior, at the very rear of the end recess of the chamber.
Sadly, this passage is now closed to public access. There is now a crack in the lintel stone that you can see in the upper right of this image. Access has been disallowed on safety grounds. The cairn has been closed since October 2018. This image was taken at spring equinox in 2017. There is no indication when the cairn might be opened to public access again. There are rumours that significant archaeological intervention might be needed, and that the cairn could be closed for a long time. I'm so grateful that I have a significant body of photographs from my many visits to its interior over the years.