It is considered historical fiction, as it is:
* Based on real historical figures: Marco Polo and the explorer's voyages to China in the 13th century.
* Blends historical facts with fictional elements: While Marco Polo existed, the book incorporates fictional characters and plotlines around the legend of the Fountain of Youth.
* Employs historical settings and events: The story is set during Marco Polo's travels and incorporates events and customs of that era.
Therefore, while the book uses historical elements as a foundation, it also incorporates fictional elements to create a narrative that is both entertaining and informative.