Sponges are strongly related to Kalymnos, known as the Kalymnian Gold. This barren rocky island located in the southeastern Aegean Sea could not offer anything to the Islanders to make their living. The villagers thus turned towards the sea for their survival and sponge fishing became particularly popular on this island.

Because it was hard for the locals to stay underwater, a rubberized diving suit called skafandro with a bronze helmet became popular allowing the sponge hunters to stay underwater for more time. Though the process was very risky, the spongers could harvest sponges in large numbers. They were later collected in warehouses for processing.

These warehouses were gradually modified into full-fledged sponge factories. There, sponges were processed in large quantities and they were sold to natives or exported. This tradition has today declined as natural sponges have been substituted by plastic sponges, made by factories in large quantities. Moreover, this process was particularly dangerous for the divers, so the locals have turned to other sources of income, such as tourism.

Only one sponge factory remains at the capital of the island, Pothia, to remind locals and visitors this tradition. This factory is open to visitors to get informed on the history of sponge-fishing, the methods used to dive, the process of elaborating sponges and to see from close enough workers elaborate sponges today.