Hjálparfoss Waterfall (on the edge of the Icelandic Highland) is an amazing site where the Fossa River meets the Thjorsa River, both emerging at an opposite angle from the Hekla volcano lava field before tumbling into their plunge pool. The lava field surrounding Hjalparfoss is composed of unique basalt formations making for a stunning landscape. Autumn is a particular beautiful time where its colors accentuate the scene.