Conference participants from all countries, including the United States, must have valid passports in order to travel to Canada. Some visitors may also need visas for entry. You are strongly advised to review your visa status and find out whether you need a visa to travel to Canada. For the United States, a helpful Web site to consult is http://www.dhs.gov/files/crossingborders/travelers.shtm. Information about Canada is available at http://www.cic.gc.ca/english/visit/visas.asp.