In class we listened to one of The Beatles' albums, Sergeant Pepper's Lonely Hearts Club Band which was essentially the first mainstream (there are concept albums from the 40's) concept album created in which throughout the album follows a storyline or theme, an example of a more recent concept album would be Kid Cudi's Man on The Moon: The End of Day which also follows a storyline throughout, but back to The Beatles, the album itself is composed of songs that technically speaking, were revolutionary in terms of recording and effects added  to the tracks themselves and added things unheard of in a music at all such as laugh track, the songs were also subject to heavy experimentation and sometimes it just seemed like they wanted to screw with people by creating the weirdest sounds imaginable.  Not so surprisingly, they still manged to make an album that I found extremely interesting to listen to as it developed and different sounds came into play.