Oxararfoss waterfall in Thingvellir, a historic site and national park. It's known for the Althing, the site of Iceland's parliament from the 10th to 18th centuries. On the site are the Thingvellir Church and the ruins of old stone shelters. The park sits in a rift valley caused by the separation of 2 tectonic plates, with rocky cliffs and fissures like the huge Almannagja fault; Blaskogabyggo, Southern Region, Iceland.