What Once Was Lost

What Once Was Lost is a soundtrack piece included in the Halo: Original Soundtrack. It primarily uses swamp noises and animal cries as undertones to add to the suspense.
==Appearances==
It plays during the start of the level 343 Guilty Spark and during a portion of Keyes when the player goes down into the big room that was encountered after entering the ship on Truth and Reconciliation. 
Category:Halo: Combat Evolved OST