You need a valid passport only.
A passport.
legal travel documents
Not necessarily. However, if you are eligible or have the documents for your travel to Canada, then yes, you can enter Canada.
Passport is a requisit.
Yes, citizens of Spain can travel to the United States with a valid passport and an approved visa or through the Visa Waiver Program.
You can visit the US side, or the Canadian side, and not go across to the other country if you don't want to. If you have travel documents, it would open up your options, but it isn't required.
None needed for travel within US
Answer: You can travel anywhere in the US. But if you want to travel outside the US you need to get a passport and file a form I-131 Application for Travel Documents ( to ensure that you can get back into the US). If you have any question you can contact the Department of Homeland Security at (800)375-5283.
All you should need is a passport and some money
The best thing to do is to go to the US Embassy in London and ask. Take your documents with you.
Travel insurance is never compulsory. It is however strongly recommended.
I have vacationed in the Dominican Republic, and the only document I had to have was my passport.