What is the ISBN of The Caryatids?

There is no ISBN for "The Caryatids" because it is not a book. It is a sculpture by the ancient Greek sculptor Alkamenes, who lived around the 5th century BC.

The Caryatids are a group of six female figures that act as supporting columns in the Erechtheion on the Acropolis in Athens.

If you are looking for information on the Caryatids, you might try searching for "Erechtheion" or "Alkamenes" in a library database or online.