Abbey Road’s Studio 2 is the famous one where The Beatles did most of their recording. The smaller Studio 3 was originally built as a place to record small ensembles (string quartets etc). By the early 1970’s Pink Floyd had claimed it as their regular home. This is a publicity photo from the time.
And this is a taste of what came out of that room:
And if you want to see how Dark Side of the Moon spookily syncs with The Wizard Of OZ, click here.