As a St. Patrick’s Day treat, here’s a great photo of one of Ireland’s most famous geologic locales, Giant’s Causeway. Formed from a Paleogene (40-50 mya) basaltic lava flow, rapid cooling and contraction resulted in some 40,000 columns and one very picturesque coastline. Photo credit goes to All That is Interesting.
Giant's Causeway, Northern Ireland
Adventures in Geology 