4th-century B.C. marble egg, a Hellenistic or Roman copy of the yet older egg (or "omphalos") in the temple of Apollo that symbolized Delphi's unique position as the center (or naval) of the world. When Zeus wanted tot determine the earth's center, he released two eagles fro Olympus. When the eagles met over Delphi, Zeus had his answer. You may still see eagles in the sky.