thingvellir rift valley of the mid atlantic ridge and historic assembly site of althing or law rock in parliament plains in

althing alafrac34 ing canyon cliff environment europe geological geology golden circle iceland green hill historical landscape icelandic law rock mid atlantic ridge mountain mountains nature outdoor parliament plains pingvellir rift rocky scenery scenic road sky south summer sunny tectonic plates map thingvellir national park valley tourism travel volcanic afrac34 ingvallavatn ingvellir