Realmonte salt mine in Sicily

 

On the southern coast of Sicily, the largest island in the Mediterranean Sea, lies the town of Realmonte, where there is a large underground mine with salt tunnels that stretch under the ground at a distance of 25 km at a depth of about 100 m underground.

The walls of the salt mine, naturally, are decorated with alternating bands of dark and light rock, located in concentric circles and stripes.

These color bars were formed approximately 5 million years ago through the deposition of salts, when sea water evaporates, leaving a large amount

 of dissolved salts in the form of sludge.

During this period, the Mediterranean Sea experienced a cycle of partial or almost complete drying, which geologists call Messinian salinity crisis.

 In those days, the Strait was firmly closed and the Mediterranean Sea has been isolated from the Atlantic, which has resulted in an increase

 in salinity.

Due to the dry climate conditions over the Millennium the Mediterranean Sea dried up almost completely, forming a deep trench, which in some places reached the mark of 3 to 5 km below the level of the MI new ocean.