At the end of Twilight Breaking Dawn Part 2, the song A thousand years plays, when Bella sends images to Edward (A trick she learned) She projects these images to him. And it brings them back to the begainning. The VERY begainning when they first met. The day he walked into the cafeteria door, Bella watching him. The time he watched her in the biology classroom. The day she found out what he was. Everything. It was like watching Edward and Bella fall in love all over again, and the song- It makes you think about how far they've come- And now they'll be forever-

https://www.youtube.com/watch?v=Am9rvhUTrpA&ab_channel=ChristinaPerri

(This is the song, it does not contain spoilers)