The Ring of Brogar is a must. Predates Stonehenge.

I attended a community variety show in Kirkwall back in 1988, and the MC told a joke about an American. He didn't know there were two of them in the audience, so after the show, I asked him if he made a habit of telling jokes about Americans. Well, of course he knew the minute I spoke that I wasn't from around there, and Annie told him I was a folk singer. Next thing I knew, we were invited to his home where we made music until the wee hours. Try that in New York city!