Svartifoss (Black Waterfall) is a waterfall in Iceland. Svartifoss has a unique polygonal pattern which can also be found in Israel ( hexagon-pool), and in the Devils Tower National Monument (in the USA). The polygonal formation was made by the slow cooling of lava layers. Lava molecules are round but when they cool down and become solid they take a polygonal shape which is the closest shape to their original round shape. These Lava columns were a siurce of inspiration to the architects who designed the famouse Hallgrímskirkja church (Reykjavík).
For more info visit Svartifoss On Wikipedia.
Google map of Svartifoss:
Next photo by Andrei Duman (visit Andrei ‘s site)