|Photo from Hayden Planetarium Website|
In Celtic mythology, the sun is of utmost importance, and the setting sun in particular is seen as a gateway to the "Otherworld." That's why so many of the structures on Inis Mor such as the wedge tombs and Dun Aengus open westward - the sun's rays which shine from the west towards the east are meant to enter these structures and fill them with sacred light.
On days when the setting sun aligns perfectly with an ancient structure (such as the summer solstice at Stonehenge), it's believed that this was a particularly holy day during which some sort of rituals were performed to worship the gods.
I don't think New Yorkers performed any rituals during Manhattanhenge, except maybe to stand in the middle of the avenues when the stoplights turned red to admire the sunset and try to snap a few photos amidst the honking of cab drivers.
I am excited that I'll be in Inis Mor this summer during the summer solstice. I wonder what rituals or celebrations I'll see, if any, at the sacred monuments on Aran...