It was mid-March 2020, and I was on edge while driving toward the entrance of Eaton Canyon Natural Area, a small slice of creek-fed greenspace that spills from the foot of Southern California’s San Gabriel Mountains into the suburban sprawl located just below. A morning hike is not my typical cause for anxiety, of course. But there was this burgeoning pandemic, you see, and I was about to join a friend for a stroll along what is arguably one of the most popular trails in all of Los Angeles County. The 3.5-mile round-trip Eaton Canyon Trail ends at a slim waterfall that pours into a placid swimming hole. It’s the stuff of every dog’s, child’s, and Instagrammer’s delight.