The Forgotten Temple is a location from The Legend of Zelda: Breath of the Wild. It is a large building found at the northernmost end of Tanagar Canyon. The Temple is filled with numerous Decayed Guardians very close to each other, which require Link to deflect their laser beams to defeat them. Koroks can be found inside, around and on top of the temple. The Forgotten Temple also features updrafts that Link can use to glide.
Near the back of the temple is the Rona Kachta Shrine. Upon entering the Shrine, Link will receive a "blessing" trial. Along with the Shrine, just behind the temple stands a massive Goddess Statue that is still smaller than the Statue of the Goddess from Skyward Sword. The statue is active and may be used to trade Spirit Orbs. A Treasure Chest containing a Giant Ancient Core can be found inside an opening by exiting the Shrine, heading the first updraft and floating down until the opening.
Sealed Temple ruins
The Forgotten Temple may be a reference to the Sealed Temple from The Legend of Zelda: Skyward Sword. This is supported with very distinct Loftwing statues at the entrance and engraved into the pillars inside, as well as the Goddess Hylia Statue indicative but not identical to the Statue of the Goddess on Skyloft. In Skyward Sword, this statue was originally part of the Sealed Grounds where the Sealed Temple was later used by Link to destroy The Imprisoned and after making a wish with the Triforce and reunited with the Sealed Temple.