Impact Crater

The Impact Crater is an area on Tallon IV. It was where a Leviathan from Phaaze, which brought the Phazon to Tallon IV, crashed. Inside the Impact Crater, Metroid Prime thrives. The Artifact Temple was built above it by the Chozo to contain the Phazon and stop it from spreading, though their efforts only managed to slow the corruption. Samus must obtain all twelve Chozo Artifacts to enter this area. It is likely that the Impact Crater was formed from the husk of the deceased Leviathan.

Areas and Main Rooms
The Crater consists of only twelve rooms, that can be divided into two areas:

Upper Caves
This area is horizontal and consistes in the elevator to the Tallon Overworld, the Crater Entry Point, which doubles as Save Station, a Missile Station, two Crater Tunnels (A and B) and the Phazon Core.

Metroid Prime's Abode
This is the area where Samus fights the Metroid Prime and consistes in the Phazon Infusion Chamber, five Subchambers (1 to 5), and the Metroid Prime's Lair.

Fauna and Flora
The Crater contains Red Phazon, and only a few lifeforms can survive in it, such as Lumigeks and Fission Metroids. The major lifeform in the area is Metroid Prime, a horribly mutated Metroid.

Trivia

 * 40.08.02 is the planetary location of the "massive energy spike" on Tallon IV: Scans of the Spiral Sector detected a massive energy spike emanating from a Wanderer-class planet identified as Tallon IV. Scout reconnaissance was immediately dispatched to the center of the spike, a land mass at heading mark 40.08.02 [...]
 * Interestingly, the Impact Crater has twelve rooms, and Samus has to collect the twelve Chozo Artifacts to enter.
 * In the New Play Control! and Metroid Prime Trilogy versions of Metroid Prime 2: Echoes, Phazon-filled rooms of Dark Aether will play the Impact Crater theme instead of the area's regular theme. Among these rooms are the Phazon Pit and Phazon Site.
 * Interestingly, the Impact Crater pinball table in Metroid Prime Pinball plays the Phazon Mines theme rather than its own. The Impact Crater theme is however used in the Metroid Mania game, however.
 * Originally, the Impact Crater was to have a Countdown, but was cut because the developers didn't want to hold the game off for one month to do it.