The Celestial Alps is an island explored in Baten Kaitos: Eternal Wings and the Lost Ocean. One of the smallest islands in the Sky, the Celestial Alps are nonetheless home to a range of mountains and remain almost entirely undeveloped and uninhabited by Humans.
Not much is known about the Celestial Alps before the events of Eternal Wings, only that Georg, an Imperial research scientist, built a secret cabin hideaway near one the peaks because of the island's remoteness and rough terrain. It's also speculated by fans that the Celestial Alps are the portion of the island of Hassaleh which was broken off during the events of Baten Kaitos Origins; important to note is that both landmasses feature mountains on their eastern halves.
During the events of Eternal Wings, the Alps are traversed by Kalas and company when he receives word from Georg's old research partner, Larikush, that his grandfather left something there for him. Upon discovering Georg's cabin, the party fights the Chaotic Trio twice and it becomes the final resting place of Giacomo. After the battle, it's discovered that Georg used the remoteness of his cabin to hide a higher-functioning Winglet for Kalas.