Once, say the ancients, Zeus tossed a thunderbolt on this place. Seated in his home atop Mount Olympus, the greatest Greek god apparently signaled with this fiery gesture that he would take up residence in Olympia, a placid place covered in olive groves on the Peloponnese Peninsula. According to the official record, the first Olympics took place here in 776 BC—a rather rural affair, held in a broad, natural stadium. Zeus’s sacred tree marked the finish line, and victors wore wreaths made from its branches, twisted into horseshoe shapes, and placed atop their heads. Fast forward to the 21st century, and I arrived here to find that I have Olympia almost entirely to myself. No cheering fans, not a single athlete—and barely any tourists. Now an out-of-the-way spot far from the main attractions, little is left to indicate that this was the birthplace of the world’s most important sporting event. …