I too have always been fascinated by accents and love trying to pinpoint them when on hols abroad. Some can be tricky. For instance Suffolk and Bristol are both wurzely even though they're geographically over a 100 miles apart.

The Mid Wales accent is a real strange one. Have a listen to Ian Woosnam and convince yourself he's Welsh.

Accents are definitely not just a UK thing. For instance listen to a New Yorker and someone from the Deep South. Couldn't sound more different.

If you want a real challenge check out Lyse Doucet, who is a journalist reporting for the BBC occasionally. When you think you've nailed the accent, have a look at her heritage. It may surprise you.