The construction of the old bonded warehouses was funded by the state and it was completed between 1834 and 1839, following the designs of the Bavaria architect J. V. Erlacher and the supervision of Wilhelm von Weiler. It is a 122 m / 400 ft long building with two symmetrical wings on each side and it's situated along the coast line. Each wing has seven storage areas. The wide, arched openings of the central gallery no longer exist. The warehouses were built in a way that the barges could access the building from the sea and unload their freight directly into the gallery. The external part of the walls was covered by medium sided stones, daubed with plaster. The eaves and the horizontal bands that connect the arches are made of tuff. The upper floor on the central part of the building was constructed a few years after on the existing basement's structure, while other additions were made later on, along with the neighbouring customhouse (between 1859 and 1861) following a form of its own.
Since the interwar period, the warehouses had ceased to function. In 1994, four storage areas on the southern side of the warehouses were rearranged for the needs of the Picture Gallery of Cyclades.