Wikipedia has a really nice map of the time zone divisions around the world. Clicking the image will take you to the full 4779x1979 map. A number of interesting political-geographic choices have been made regarding time zones. China is huge, but keeps everything in the same time zone. Europe is pretty wide, but also keeps mostly in 1 time zone. The UK is close enough geographically to be in time with Europe, but is 1 hour off instead. India and some other countries are 30 minutes off the normal hours. It's an entertaining hodgepodge.