Thirteen years ago this week, Apple shook up the music industry with the launch of the first generation of iPod and while it may have come with a physical scroll wheel, huge hold switch and a FireWire port with cover, it made listening to music on the go much cooler.

The iPod is far from the only MP3 music player around and while it may not get as much attention as Apple's iPhone, especially not now as the iPhone can do everything the iPod can, it's still a product almost everyone will have heard of, even if they have no idea what it actually does.

A lot has changed since the first generation model was introduced all those years ago though, and not only has the iPod's design been redefined significantly, there are now a few models, colours and storage options to choose from.

To celebrate the iPod turning into a teenager, we have hopped in the time machine and taken a look back at all the generations of models to see how things changed and how far the iPod has come in terms of design. You'll be surprised how something that was so cool at the time looks so dated now. Enjoy them as Apple has already discontinued the iPod classic so who knows how much longer you have left to appreciate the others before they become obsolete too.