Story related, can’t be missed.
*** Spoiler - click to reveal ***This is during the Volcano Core after you've killed Scylla. You'll have to escape from the volcano’s eruption by climbing a wall out of the volcano. Once you've climbed your way out of the volcano's eruption to safety, Atlantis is unfortunately not so lucky and is destroyed thus unlocking your trophy.
All credit goes to orginal authors at playstationtrophies.org, and this is merely updating truetrophy fans with these guides.
http://www.playstationtrophies.org/game/god-of-war-ghost-of-...