Useful Information for English speaking Visitors (more pictures inside): Article that for the balcony holders (cantilevers) designs & materials, during the Greek neoclassical era (~ 1835 to ~ 1930), when they became unneeded on the new buildings from reinforced concrete. Most of the marble holders are handmade pieces of art, made exactly from the same material, as the ancient buildings of Acropolis: the unique white marble of Penteli mountain in Attica. Only a few artists still create new holders today, that are very expensive.