Once Upon a Time...

[7] Most of the others are more focused on specified historical fields, such as the lives and exploits of the explorers or inventors,[8] except for Space and Life.

The former was a science fiction series,[9] while the latter featured an explanation on the workings of the body.

"Life" is the only one to not feature the children as grown-up or adolescent archetypes of said characters, but as parts of the human organism.

[10][11] Most of the series are in the animated documentary genre and teach in an expository style.

Maestro had the role of Leonardo da Vinci[12] and mostly of benevolent or enlightened rulers (amongst these, he surprisingly represented Kublai Khan).