European Union citizens require a valid national identification or passport to travel across Europe. Citizens of other European states, as well as citizens of the United States, Canada, Australia and New Zealand require a valid passport to enter the EU. Both categories of travelers do not require a visa if they intend to travel as tourists and the length of their intended stay does not exceed 90 days.
All visitors to Europe wishing to stay longer than 90 days or seeking to obtain a work or residence permit may require a visa. You should consult an embassy or a consulate of the desired country of destination for more information.
Please note that permanent residents of Canada who are not EU or USA citizens do not qualify for visa exemptions and should apply for a visa prior to departure.
U.S. citizens entering Canada require a valid passport, and the same holds true for Canadians travelling to the U.S. The former rule of identity cards accepted at the border no longer applies. Having a passport with you is always a good idea regardless of the country you are travelling to: passports are recognized worldwide as acceptable proofs of nationality and identity.