What's an album where people claim that nothing was the same after it was released, an album that not only shook up the music world going forward but that hugely impacted pop culture as well?

I'm going to go with The Beatles Sgt. Peppers Lonely Hearts Club Band. This was the album that proved to the world that pop/rock music could also truly be high art, it was touchstone in the development of the concept album, and it captured perfectly the mysticism and optimism and non-conformity of youth culture of the time.