Þingvellir National Park, at the northern end of Þingvallavatn—Iceland's largest lake—is a potent symbol of Icelandic heritage. Many national celebrations are held here, and it was named a UNESCO World Heritage Site in 2004. Besides its historic interest, Þingvellir holds a special appeal for naturalists: it is the geologic meeting point of two continents. At Almannagjá, on the west side of the plain, is the easternmost edge of the North American tectonic plate,
otherwise submerged in the Atlantic Ocean. Over on the plain's east side, at the Heiðargjá Gorge, you are at the westernmost edge of the Eurasian plate.
A path down into Almannagjá from the top of the gorge overlooking Þingvellir leads straight to the high rock wall of Lögberg (Law Rock), where the person chosen as guardian of the laws would recite them from memory. At the far end of the gorge is the Öxarárfoss (Öxará Waterfall). Beautiful, peaceful picnic spots are a bit beyond it. Just behind Logberg the river cascades down and forms the forbidding Drekkingarhylur pool, where women were drowned during the late middle ages.