When we got off the bus, at around 6 A.M., it was pitch dark, and the fields of Salisbury Plain were sodden after a night of desultory rain. Most of the passengers—who included a retired physicist and his wife, and a pair of young lovers peering at their smartphones while audibly pining for hot chocolate—were dismayed to learn that the bus would go no farther. To our right, the new Stonehenge Visitor Center, an elegantly wispy structure with more than two hundred slender, tilted pillars and an undulating steel roof, was a blur in the murk. The standing stones were a mile and a half to the southeast. It was too blustery for umbrellas, so those of us with hoods pulled them over our heads, and we all started walking. The sun would not rise for more than two hours: it was the winter solstice, the darkest day of the year.