Thingvellir National Park has to be one of the most geologically fascinating sites I have visited, sitting atop the rift between the North American and the Eurasian tectonic plates. It isn't the geology on its own which got this park inscribed as a World Heritage Site, though it provides a stunning backdrop, particularly in winter as the black basalt cliffs stand in stark contrast to the snowy plains. But the geology is what made this an ideal site for the founding of the Althing, the oldest parliament in the world, which met at Thingvellir annually. At the base of the cliff formed by the edge of the North American plate is a rock outcropping the Icelandic people call the Lögberg, or Law Rock, which is now marked by an Icelandic flag. Here, the legislature would meet, and the law would be read to the people gathered on the plains below. The assembly was open to all free men, who would bring their families and camp on the fields of the rift valley in what must have been an incredible social gathering. The Althing no longer meets at Thingvellir, having moved to the Icelandic capital of Reykjavik almost 175 years ago. Still, Thingvellir National Park is a stunning site to see, and, after having visited the site this past January, I would love to return to see it in summer.
Logistics: Thingvellir National Park can be reached by numerous tours operating out of Reykjavik or by private transporation; there are numerous trails on site, as well as parking lots above and below the Althing site.