The Sky Garden of Babylon (バビロンの「空中庭園」,Babiron no "Kūchū Teien"?, literally "Aerial Garden of Babylon") is one of the nine legacies from the foremost genius Doctor 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 Partheno (古代文明パルテノ,Kodaibunmei Paruteno?). It is the first piece of Babylon to be discovered by Touya.
The Sky Garden was created as a hobby by the doctor 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 Partheno 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 Storehouse.
Touya accesses the garden, through a portal in the underwater Niruya ruins, located on a remote island near the southernmost island in the Eashen territory.
After establishing relations with the island nation of Palerius, Doctor Babylon placed her own version of the Dimensional Transfer Gate along with a magic storage tank for later use.
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.
It became their primary method of transportation when Touya's 【Gate】 could not be used.
The ruins where its research circle is located are most likely based on the Yonaguni Monument, a mysterious collection of rocks off the coast of southern Okinawa, that some think may be a form of manmade monoliths