On the Acropolis overlooking Athens, across from the Parthenon, is the Erechtheion. The most notable part of the structure is the Porch of the Caryatids, female sculptures designed to act as pillars for the porch.

The description is very short:
ATHENS: Portico of the Caryatides
The original marble statues have been removed and replaced with castings, since the intense pollution and acidic rain of modern Athens was literally melting the marble away. This photo shows them before removal and the beginning of extensive renovation of the structure.
The postcard was used and has the date of June 4, 1977.