On August 21, 2017, a total solar eclipse crossed the entire United States for the first time in 99 years. NASA estimated 215 million people watched it. People drove 12 hours. Traffic jammed for 100 miles outside the path. Strangers pulled over on highways and lay on their backs in parking lots.
Nobody told them to. They just went.
For 2 minutes and 40 seconds, the sky went dark, and everyone forgot what they had been doing.
That's the eclipse effect. No announcement. No explanation. Just presence that changes the atmosphere of everything around it.
