Cairn G, Carrowkeel, in the mist

Cairn G, one of a complex of Neolithic chambered cairns at Carrowkeel, on the Bricklieve Mountains, County Sligo, pictured in the early morning fog. Cairn G is the only known passage-tomb in Ireland, apart from Newgrange, to have a 'roof box' or false lintel above its entrance doorway. This photo was taken on an autumn morning which was full of atmosphere. My climb to the cairns was completely shrouded in dense fog, so that at times I could barely see 10 metres in front of me. However, my efforts were rewarded with this very atmospheric image. 

The cairns of Carrowkeel were excavated in 1911 by RAS Macalister and Robert Lloyd Praeger. They are situated on limestone mountains overlooking Lough Arrow, and are believed to be older than the great megalithic monuments of Brú na Bóinne.