If I wanted to travel the world and live in different countries, would I need a work permit to work there?

In most countries, yes. You would also need to speak the local language,

Hi Snip, yes, you need to have a work permit to officially work in almost all countries, however, you won't get one. In general this is not a biggie, because very often you can work for a shorter period of time without a permit, but it also depends what countries you wanna visit. I travelled 10 months through Central and South America last year. You can find jobs at some hostels (usally a only a few hours a day). They won't pay you any money, but you can stay for free, and some of them give you one or two meals a day. You can teach english, but should have an ESL certificate, however, you would need to stay for a longer period of time in one place. If you plan to travel to Europe, it is a bit more difficult since everything is very regulated over there and also enforced by the authorities. When I was in Granada/Nicaragua for example the local gym (U.S. owner) was always looking for personal trainers, yoga instructors, etc. in exchange for free stay and some food. Good luck.

If you go to Latin america work permits and stuff aren't so heavily enforced. I worked in Venezuela for a year on a tourist visa. The last 3 months My visa was expired(I was illegal) and after being stopped by army and national guard many times without a problem, I got stopped by a cop who noticed the dates on my passport. When I told him I was going to marry my venezuelan girlfriend and leave in like a week he let me go. Usually down there cops want you to pay them money, but it depends on where so be careful, bribing in ecuador is a big nono. Venezuela, its the norm, as well as mexico, colombia, its so/so. But its hard to get a job without speaking the lingo.