ANDREA CIPRIANI MECCHI

MARLEY DIAS, 12, loves getting lost in a book. But she was frustrated by the books she was reading. The main character was hardly ever a black girl. So in November 2015, Marley made a plan. She set out to gather 1,000 books featuring black girls. She started a campaign called #1000blackgirlbooks.

Marley's campaign was a big success. She collected more than 10,000 books.

"I want to give kids a stronger sense of identity," Marley told TFK. "The biggest thing I've learned is that kids' voices need to be heard."

Now Marley is working on a book of her own. Marley Dias Gets It Done and So Can You comes out this winter. The book is about activism. That means making change happen. "Anybody is able to give back," Marley says. "But my main tip is you should always follow your passion."