If a Bus Could Talk by Faith Ringgold
This book is about a bus that tells the story of an African-American your girl named Rosa. She has to walk down many miles to get to her school in Alabama while she sees white children getting there in a bus. Then, the adult Rosa will go to work on a segregated city bus and couldn’t sit in the same row as a white person. It is an incredible journey to read about, teaching little kids values and morals about the history and evolution.
You can find the book here: If a Bus Could Talk by Faith Ringgold