silfra thingvellir park. silfra breakdown of the tectonic plates of the mid-atlantic ridge

atlantic background basalt beautiful blue breakdown canyon countryside crack cracked crevice drift environment famous fissure flow geological geology grass green horizontal iceland icelandic landmark landscape lava mid midatlantic national natural nature park plate plates ridge rift river rock scenery scenic silfra sky summer tectonic tectonics thingvellir travel unesco valley view water