The Dead Sea is a giant, super-saline lake at the lowest spot on Earth. And its beaches appear to be pebbled with perfect little cubes of salt.
Crystal solids with flat sides like salt are symmetrical in shape because their molecules are arranged in a repeating pattern of positive and negative ions; the bonds between these electrons and protons are formed from electrostatic forces. Salt crystals are always cube-shaped, though impurities can cause crystals to grow into jagged chunks.
Check out the Dead Sea salt cubes in this video:
The legendary sea links Israel and Jordan, though its shoreline has been moving ever since the sea’s been shrinking. People have been drawing large amounts of water from the rivers that feed it, and as the lake recedes, it leaves behind massive stores of solid salt in underground cavities. And when fresh water aquifers diffuse into those salt deposits, they create sinkholes — at least a thousand of them have been found. Some scientists say the Dead Sea will be a puddle by 2055.