London's talking buses with some ambiance for good measure. Numbers 7 and 31:

Buses sound different in every country believe it or not, and when you take a bus you may not even realise it as you take it for granted, or you're commuting on your way to work and don't care. That having been said, if you do stop and listen, you'll notice a huge amount of interesting conversation, ambiance and general outside noise and sometimes it's interesting. Take these two buses, numbers 7 and 31 respectively. The ambiance is different, the engines sound different, the 31 is probably a newer model, and the beep used to signify the closing door is different between buses. If you live outside of the UK, or even if you live outside of London, I hope you get a small insight into a London bus and enjoy it.