I think that this song is meant to be like an Apocolyptic type of senario. In the first line it talks about a brand new skiyline and it later says that they mourn the dead. I imagine that it's like "I Am Legend" when he's the last one left. Later on in the song it talks about covering up the lies, so it must of been something man-made instead of something divine. It also talks about breathing with broken lungs, so maybe something airborne.
That's just my idead off of the song, you can take it however you want. : D