None.... except illegal ones - which don't get a visa anyway. You will be going on a tourist entry (visa free, using ESTA) and the rules are 1) No work, 2) No looking for work! 3) looking, seeing and spending (as a tourist) only 4) return ticket in your hand (and you are sensible if you have health and accident travel insurance esp in the US) 5) ability (if asked) to show that you 'need' to go home - so a job or at school back in the UK now, Canada.... if you are 18 - 30, you are able to obtain a 'working holiday' visa otherwise known as International (Youth) experience Visa.
http://www.cic.gc.ca/english/work/iec/ and... at Canada whilst different is also very similar, and much closer (if you want to visit) If you want a job in the USA (or any country entering on a Visitor visa). You need to have arranged the interview in advance - and it becomes a business visit (to do the interview), after which you go home and apply for a work visa with company sponsorship. As that takes 10,000's you have to be pretty special to justify you over a local who can work without a visa (!).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.