How does humor change from country to country?

Do you think the sense of humor of different cultures or countries varies? How would you describe humor where you live compared to elsewhere around the world?

For example, I think Japan has a more physical style of self-depreciating humor (google Japanese game shows and you’ll see what I mean). Whilst some say British humor is more ‘dark’ and ‘dry’. What do you think? And why do you think it differs? Use some examples if you want too.