On the first day of her climate strike, Thunberg was alone. She sat slumped on the ground, seeming barely bigger than her backpack. It was an unusually chilly August day. She posted about her strike on social media, and a few journalists came by to talk to her, but most of the day she was on her own. She ate her packed lunch of bean pasta with salt, and at 3 o’clock in the afternoon, when she’d normally leave school, her father picked her up and they biked home.On the second day, a stranger joined her. “That was a big step, from one to two,” she recalls. “This is not about me striking; this is now us striking from school.” A few days later, a handful more came. A Greenpeace activist brought vegan pad thai, which Thunberg tried for the first time. They were suddenly a group: one person refusing to accept the status quo had become two, then eight, then 40, then hundreds. Then thousands.