Rectangular Valley
From Transformers Wiki
The Rectangular Valley (矩形の谷 Kukei no Tani) is an underground temple located within a mountain range on Animatron.
Fiction
Beast Wars Reborn
After Backstop found Optimus Primal, the Animatronian led the alien Transformer to the Rectangular Valley so that they with the temple's priests could use its Transformer technology to decipher the information on the Golden Disk.
Days later, Megatron came with an army for the Golden Disk and used his new Cyber Key power to destroy the Rectangular Valley. The Extraordinary Reformat