The peaks of Mount Parnassus shimmered on a warm spring afternoon above the temples of ancient Delphi. In a verdant valley below, silver-tipped olive trees stretched to the sea. The sun traced a golden arc in the azure sky. On a flat plateau surrounded by this natural theater, I looked up to find myself standing at the center of the world.

At least, the center of all things as the ancient Greeks knew it. In front of me was a black ovoid stone, known as the omphalos, set on the spot in Greek mythology where two eagles loosed by Zeus crossed paths at the earth’s nexus. It marked Delphi as one of the greatest enigmas of the ancient universe.

I had come for what was supposed to be an afternoon visit during a recent trip to Athens. Delphi is best known as the home of the famous Oracle — a powerful priestess who saw the future of kings and nations — and I wanted at least a glimpse of the mystery before pressing ahead with my travels.