The Gaia Temples (ガイア神殿 Gaia Shinden?) are a set of seven ancient temples that appeared in Sonic Unleashed and are located around the world. By grasping the very power of the planet itself and with the aid of the Chaos Emeralds, these temples have the ability to bring the world back together when it is broken into pieces by Dark Gaia following the Time of Awakening, and as well restore the Chaos Emeralds should they lose their power. If all seven Chaos Emeralds are brought to their respective temples, then the world will be whole again. They have a strong connection to Light Gaia.
According to the Gaia Manuscripts, the Gaia Temples were created "ages ago" (presumably at least tens of thousands of years ago) by an unknown civilization at different points across the globe. Their function is to harness the very power of the planet itself and work in sync with the Chaos Emeralds, with the purpose of putting the world back together whenever it is broken into several pieces by awakening of Dark Gaia and seal up Dark Gaia itself. Their ability to harness the planet's power also act as a mean of restoring the Chaos Emeralds' power in the case they have been drained of them.
Since Light Gaia has been the one performing the process of restoring the planet since the beginning of time, it may be possible that the Gaia Temples were created as a contingency plan should Light Gaia fail to stop Dark Gaia, or most likely aid him should he be unable to restore the planet on his own.
The process of restoring the planet and sealing Dark Gaia is through placing the seven Chaos Emeralds in a small alter found in the center of the temple. The emeralds' power will then provide the energy needed for the Gaia Temples to help the Earth heal naturally from Dark Gaia's awakening. In the case the emeralds have been drained of their power, placing them in the alter will cause the emeralds to be recharged through the planet's power. In turn the act of the emeralds being recharged leads to the equal and opposite reaction of the emeralds healing the Earth.
Chip shares a special connection with the temples, due to the fact that they share the job of restoring the planet's condition and possibly because the Gaia Temples were built to aid him. With Chip's innate Light Gaia powers he can activate the altar and reveal the hole for the Chaos Emerald to be placed and can also sense the location of the temples after realizing his identity. It is within Adabat's Gaia Temple that his memory is restored, which suggest that the Gaia Temples might contain Chip's essence or act as extensions of himself. As seen during the battle with Dark Gaia, Chip is able to call the Gaia Temples to his location in times of self-defense in order to form the body of the Gaia Colossus.
In Sonic Unleashed, Dr. Eggman learned about the Gaia Temples from the Gaia Manuscripts. After somewhat successfully awakening Dark Gaia with his Chaos Energy Cannon, the doctor sought to secure the Gaia Temples as they could prove to be a threat to his plans. Meanwhile, Sonic the Hedgehog and Chip (aka. Light Gaia) began seeking out the Gaia Temples in order to restore the planet and stop Dark Gaia's resurrection.
Not long afterward, Dr. Eggman learned that Sonic was still alive from their last encounter, and as such deployed his forces to the Gaia Temples to slow down Sonic while completing his plans with Dark Gaia's energies. These efforts proved to be in vain, as Sonic and Chip was successful in reaching all seven temples, stopping the doctor's plans and put the world back together. In the process of the restoration of the final continent, the Gaia Temples were called together by Chip to form the Gaia Colossus in the insuring battle with Dark Gaia and later Perfect Dark Gaia.
All of the Gaia Temples were presumably destroyed when Chip and the Gaia Colossus were resealed inside the Earth's core following the defeat of Perfect Dark Gaia.
- Mazuri: Guarded by Dr. Eggman's Egg Beetle.
- Chun-Nan: Guarded by the Dark Gaia Phoenix.
- Spagonia: Guarded by Dr. Eggman's Egg Devil Ray.
- Holoska: Guarded by Dark Moray.
- Shamar: Guarded by the Dark Guardian.
- Adabat: Guarded by Dr. Eggman's Egg Lancer.
- Eggmanland: Unguarded, although the player does fight Dr. Eggman's Egg Dragoon after restoring this temple.
As shown on the PS2/Wii version of Sonic Unleashed, each Gaia Temple (except the one in Eggmanland) has one or more appointed human guardians who watches over the Gaia Temples and deem whether a person are worthy to use the Gaia Gates that lead to the temples. These people are the latest in a long line of guardians who have watched over the temples since ancient times. These people are also the only ones who can assemble a Planet Tablet. The following known guardians are:
- Gwek - guardian of Mazuri's Gaia Temple.
- Zonshen and the Dark Gaia Phoenix - guardians of Chun-Nan's Gaia Temple.
- Otto and Lucia - guardians of Spagonia's Gaia Temple.
- Sarianna and Jari-Thure - guardians of Holoska's Gaia Temple
- Ehsan - guardian of Shamar's Gaia Temple.
- Teanchai - guardian of Adabat's Gaia Temple
- While it is unknown what kind of civilization that created the Gaia Temples, this civilization is the oldest confirmed civilization presented in the Sonic the Hedgehog series so far; the Black Arms are said to have visited Earth for about 2000 years, and the Knuckles Clan and the Nocturnus Clan are confirmed to go as far back as 4000 years, while the civilization that created the Gaia Temples goes as far back as at least tens of thousands of years.