The thirty-ninth classical recording: #853 Benjamin Britten - The Young Person's Guide to the Orchestra
I realise we didn't listen to the full version of this work, as apparently narration can be used to introduce the different instruments as they come in, each playing a variation of the theme suited for that instrument. It lets you understand where the various instruments fit in and how they can be used in different ways. It feels like a more unique structure, but one that works by showcasing individual parts, rather than building on each other as we normally, often, see.