The Sky Garden of Babylon (バビロンの「空中庭園」 Babiron no "Kūchū Teien"?, literally meaning "Aerial Garden of Babylon") is one of the nine legacies from the foremost genius Professor Babylon which is created approximately more than 5000 years ago before being found by Touya Mochizuki. It was created using the technology of the Ancient Civilization Paruteno (古代文明パルテノ Kodaibunmei Paruteno?).
The Sky Garden was created as a hobby by the professor and a android named Francesca was employed to manage everything within the garden. It is called as sky garden because it is floating in the sky and has four Paruteno Dome which granted the garden invisibility. The garden itself resembles a botanical garden that was enchanted with durability and sustainability which minimizing its maintenance. According to Francesca, some people used to call the Sky Garden as Nirai Kanai (ニライカナイ Niraikanai?). Because of the peaceful and relaxing atmosphere created by the garden architecture, it used as a place for healing one's mind.
The Sky Garden happened to encountered other Babylon around 3028 years ago with The Library and 985 years ago with The Warehouse.
Touya accesses the garden, through a portal in the Niruya ruins, underwater.
- The epithet given to Sky Garden, Nirai Kanai, is based on the Ryukyuan religion. It is a place where gods take crops and farming tools for their people.