We just returned from Newgrange, a Neolithic tomb built over 5,000 years ago. The tomb is thought to have been used not only for burial, but for other rites and rituals - so perhaps better classified as a temple. It looks like a large mound and is surrounded by beautiful countryside and a nearby river. It isn't hard to imagine why this area was settled by agriculturalists so long ago.
You can go inside the mound into the tomb itself, but the area is protected, and you will need to be accompanied by a guide. (Before it was protected, many visitors came and went, and there is no knowing what they might have taken with them. You can see evidence of what they left behind though in the form of graffiti inside). The passageway is pretty low and narrow - both Jeff and I happen to be Neolithic-sized people, so it wasn't bad for us - but it's definitely a squeeze for people of larger stature. It opens up once you arrive in the inner chamber, and you can admire the neolithic carvings on the walls and ceiling, and the roof of the chamber which has never had to be reinforced or reconstructed, and has remained completely watertight for 5,000 years, despite millenia of not infrequent rainfall.
One of the things Newgrange is famous for is the fact that it was built so that at winter solstice (December 21st) the sunrise lines up perfectly with an opening above the entrance (called the roof box), illumunating the passageway and chamber in golden light. Our guide showed us a simulation with artificial light, which was pretty fascinating. To see the real thing, though, you have to enter a lottery, and once you win, keep your fingers and toes crossed that your December 21st happens to be a sunny one.
Winter soltice notwithstanding, it is pretty incredible to stand inside the tomb and contemplate what it meant to the people who built it, how they used it, what the art work means, and what considerable effort and sophistication went into its construction. I think that we sometimes tend to view ourselves as superior to early peoples - in terms of intellect, technology, etc. However, standing inside this 5,000 year old structure, I find it pretty apparent that we are not so different from them at all, and our achievements do not exceed theirs, but rather have been built upon them.