On November 26, 1859, when Ermoupolis was the center of telecommunications and telegraphy in the Mediterranean, the underwater cable Syros – Piraeus was laid, from the two-story building located directly below the large monumental complex of the purgatory, known as the Lazaretto. The building, which later became known as the “Telephone Office”, was built together with the Purgatory in 1839-1841 by Wilhelm von Weiler at the government’s behest and expense, as a Warehouse, probably of the Purgatory. Built close to the sea, in a prominent position at the southern end of the port, in Pidali Bay, it is an iconic building, but unknown to most of the world, unique for its surviving mechanical equipment, in one of the most important positions on the island. Telegraph cables remain in the seabeds, now inactive with the evolution of communications.

A sample of them is preserved in the building’s tanks, while its superstructure preserves the tool equipment of the era of telegraphy. Strange machines, shafts, parts and screws rusted and inactive for many years, which reveal the very important role of Syros in the matter of communications at that time and make the building a precious ark of industrial history, a preserved monument of industrial archaeology.