Sierra 117

Landfall is believed to be the first campaign mission of Halo 3.

It takes place in a jungle.

It was likely named because SPARTAN-117 disembarks from the Forerunner Ship onto the lands of Earth, although this is unconfirmed.

Upon completing it on the Normal, Heroic, or Legendary difficulties, the player will earn the "Landfall" achievement and 20 Gamerpoints.