Garðar Cliff at Reynisdrangar

These striking "organ pipe" structures are a textbook example of columnar basalt. This geometric phenomenon occurs when a thick layer of lava cools very slowly. As the molten rock solidifies, it contracts and cracks in a highly organized pattern—typically forming hexagonal or pentagonal columns. The cooling process starts from the outside in; the cracks propagate downward, creating the perfectly vertical pillars seen at the Garðar cliff. These columns are so symmetrical they often appear hand-carved, but they are entirely the result of thermal physics and volcanic history.