The Sealed Grounds are the place where Hylia gathered the people that survived the conflict with Demise and sent them to the sky. It is also the place where The Demon King Demise was sealed [1].
Temple Complex
The Temple of Hylia, also known as the Sealed Temple, remained on the Surface, sans the Goddess Statue, which was on the land that the goddess sent to the sky [1].
Location
The Temple of Hylia is said to be located at the "Center of the World"[note 1]. In the Era of Chaos, Rauru built the Temple of Light in the "Center of the Sacred Realm" in order to guard the Triforce[2]. Hyrule Historia also states that "It is thought that Rauru built the Temple of Time directly over the ruins of the Sealed Temple". With the release of The Legend of Zelda: Tears of the Kingdom Masterworks, we can observe that the Temple of Light was built directly over top of the Sealed Grounds[3], which would imply that the area above the Sealed Grounds is also the Sacred Realm. It could mean that theory that he built the Temple of Time over top of the Sealed Grounds was merely an in-universe rumor.
Notes
- ↑ The exact meaning of "Center" is unknown here. The images showing the Sealed Grounds in The Legend of Zelda: Hyrule Historia depict the bottom of the spiral pit as the Sealed Grounds. The Legend of Zelda: Tears of the Kingdom Masterworks provides a diagram detailing Hyrule Castle Chasm as well as the Forgotten Foundation in which it details that the very bottom of the Forgotten Foundation are the Ruins of the Era of the Gods. It goes on to show that the Sealed Grounds are at the very bottom, where Gloom's Origin is currently located, with the Temple of Light built over top of that. This provides proof that "center" is intended to mean the literal center of the world and not the center of a topographical map
