Lyric discussion by DerangedHippo13 

Cover art for Souvenirs lyrics by Architecture in Helsinki

I think this song is just about how you can't go back in time, all you've got is your memories, and you're constantly wondering if you got it right.

"I’ve got souvenirs but yesterday can’t mean too much, have we missed an opportunity."

souvenirs being memories. yesterday can't mean to much because otherwise you'd just be constantly stuck in the past.

idk. thats the vibe that I got from it. definitly a brilliant song though.