Wikimedia
Wikipedia: Oracle
This article explains what an oracle is and discusses some of the prominent oracles in classical Greece, primarily the one at the temple of Apollo in Delphi. Links are also provided for additional information.
Other
Student Reader: Hellenic vs Hellenistic Civilization
Explains the differences between the Hellenic and Hellenistic ages. The Hellenic age was prior to the time of Alexander the Great, and the Hellenistic age followed it.
PBS
Pbs: The Rest of the World in Time of Classical Greece
A summary of what was happening in other world cultures during the Classical period in ancient Greece.
Other
The Athena of Piraeus
A picture and description of the Athena of Piraeus, a famous bronze of the goddess. Part of a larger site dedicated to all things related to Athena, including a timeline and online galleries of images of Athena in paintings and sculpture.