It was 44 years ago that...

Parlaphone released the Beatles 'Sgt. Pepper's Lonely Hearts Club Band'.
What other albums can be considered having as much impact, actually altering the direction of a music genre?
I'm amazed no one has mentioned the Beach Boys "Pet Sounds". Arguably the most influential album ever, including the Fab Four.
Hi Hack,
You're right. Pet Sounds came out over a year earlier. I do recall seeing an interview recorded around that time, of John saying how much Pet Sounds played a influence on Sgt Pepper.

These questions beg multiple answers that only go to prove that life can't be reduced so facilely ... I do remember a
DJ playing "Palisades Park" about 10 times in a row one night many, many years ago ... and subsequently getting fired for same. I certainly remember "Blue Suede Shoes" and that Elvis look ... I still listen to Coltrane's "Interstellar" and "Ascension," something I can't say about the majority of my music ... I appreciate the Stones much more today than was true years ago, and I still think the Doors put out some of the best rock/blues ever produced
I'll throw Joy Division's Closer on the table. It had a large influence on the rock bands that came after them. Nothing like the Beatles will exist again. They were a cultural event.
The Cars first album.