Artifact Temple

The Artifact Temple is a building created by the Chozo to contain the spread of Phazon on Tallon IV. It is sometimes referred to as the "Cradle" in Chozo Lore. The temple was later opened by Samus Aran to confront Metroid Prime.

Background
The Chozo were a prosperous race that had colonies on several worlds, including Zebes, SR388, Elysia and Tallon IV. But they prophesied their own destruction, foretelling that something called "the Worm" would threaten them, and that the "Newborn" would come and encounter the "Worm".

This prophecy came to pass when Tallon IV was struck by a Leviathan. When it made contact, everything changed. Local flora and fauna were horribly mutated, and the environment itself became poisoned. The Chozo attempted to seal away the Leviathan, along with the "Worm" it had brought, constructing the Artifact Temple ("Cradle") over it. However, despite their efforts, the Phazon brought by the Leviathan had already poisoned their world. As they finished the Artifact Temple, they were soon driven mad from Phazon Sickness. The worm however, was successfully detained in the Impact Crater below the temple, as the poison the Leviathan carried continued to spread across Tallon IV.

Metroid Prime
During her time on Tallon IV, Samus Aran discovered the Temple. After learning from several Chozo lore entries that the prophecy was for Samus to destroy Metroid Prime, she gathered the twelve Chozo Artifacts necessary to unlock the Temple to access the Impact Crater. She eventually destroyed the source of the Phazon, Metroid Prime.