A prehistoric stone fort with three concentric ramparts, perched on a 100-metre Atlantic sea cliff at the western end of Inis Mór — the largest of the Aran Islands. Built around 1,100 BCE in the late Bronze Age, half its enclosure has been lost to the cliff that the Atlantic keeps eating. There is no fence at the cliff edge. You can lie on your stomach and look straight down.

The fort sits in one of Ireland’s last living Gaeltacht regions, where Gaeilge (Irish) is still the everyday community language. Children grow up bilingual. Pubs in Kilronan run Wednesday-night sessions in Irish.

Pro tip: walk or rent a bike from Kilronan port (7 km, ~40 min cycle, beautiful coastal road). Stay overnight if possible — the islands transform when the day-trippers leave on the last ferry.