Ar Tonelico: Melody of Elemia - Part 01

Ar tonelico takes place in the world of Sol Ciel (ソル・シエール), which literally translates to "Sun Sky" in Latin and French, respectively, but means "Shining Sky/World" in the game's own language. The world consists of the living Tower of Ar tonelico and the Wings of Horus, a landmass connected to the lower portion of the Tower. Each section of the world above and below The Wings of Horus is designated with a specific name. The lower world is known for its small towns and is not considered to be very technologically advanced. The upper world is very advanced, and the Floating City of Platina is even considered to be a holy sanctuary by the Church of Elemia from the lower world. The Tower exists at the center of the world and is made from technology that was available prior to the world-destroying catastrophe known as the Grathnode Inferia. There is little land left after the two catastrophes of the past, so people have become increasingly dependent on Ar tonelico. The Tower functions much like a computer program, and is susceptible to viruses which are emerging at an alarming rate to wreak havoc on both the upper and lower worlds.

https://en.wikipedia.org/wiki/Ar_Tonelico:_Melody_of_Elemia

https://www.metacritic.com/game/playstation-2/ar-tonelico-melody-of-elemia