My youngest was three and we had to catch two buses to nursery, and during one journey she saw her first black person, a gentleman aged about sixty. She stared at him for some time, and then confided in me in a voice loud enough for the entire lower deck to hear - "Daddy, that man's got black skin!" and he smiled at her, and she smiled back.
Having studied him for a few more minutes, she observed in a similarly valuminous 'stage whisper' - "He's got black EARS!"
Priceless.