This is the 6333rd most frequent Russian word.
фантазии
Imagination or fantasies.
The word 'фантазии' here denotes the imaginative and creative ideas or thoughts someone possesses.
У неё богатые фантазии.
She has rich imaginations.
'фантазиям' in this context means unrealistic or fictitious ideas or scenarios created by someone, which may not be truthful or real.
Не стоит верить его фантазиям.
You shouldn't believe his fantasies.
Here, 'фантазий' reflects the creative and artistic ideas that children have and should be allowed to express.