We left Dublin today and got to see a bit of why this is called the Emerald Isle. We took a tour out to the Hill of Tara and Brú na Bóinne, two sites that date back to the Stone Age.
Tara is a commanding hill that was once the seat of power of the High King of Ireland (and was said to have been used even earlier). It's been raining intermittently for the past few days, so we were extraordinarily lucky to reach Tara during a clear spell. The resulting views were spectacular: a sunlit deep green countryside beneath dramatic clouds.
After a stop at a working farm, we continued to Newgrange, one of the three large "passage tombs" in the region. About 5000 years ago, people with no metal tools managed to build a 60 foot long passageway of standing stones and lintels ending in a domed chamber precisely enough that for approximately 20 minutes on one day a year (assuming it's not overcast), light shines through a small window and illuminates the chamber. It's estimated that they moved about 200,000 tons of rock to do so. It's pretty mind boggling.