The Mysterious Cities of Gold, originally released in Japan as Esteban, Child of the Sun and released in France and Luxembourg as Les Mystérieuses Cités d'Or, is an animated series which was co-produced by DiC Audiovisuel and Studio Pierrot.

Pierrot Co., Ltd. is a Japanese animation studio established in May 1979 by Yuji Nunokawa, previously an animator and director for Tatsunoko Production. Its headquarters are located in Mitaka, Tokyo. Pierrot is renowned for several worldwide popular anime series, such as Naruto, Bleach, Tokyo Ghoul, Yu Yu Hakusho, Black Clover, Boruto: Naruto Next Generations, Ghost Stories, Great Teacher Onizuka, and Saiyuki.