In November of 2003 I went to Ireland for a week and a half. While there I got to tour New Grange, one of the oldest neolithic sites we have preserved in the world today. They have a limit on the number of visitors allowed through each year, so I felt quite honored. It was a highlight of my trip.
Repeated outside and inside the structure is an interlocking swirl pattern that really caught my eye. The significance of it is not known, although there are many learned opinion on the matter.
but I'll leave the corned beef and cabbage for those made of sterner stuff.