A passport is a document, normally in the form of a small book that has several functions. A passport enables a person to travel outside of the borders of their home country. Although a passport does not automatically grant the holder the right to enter any country, US and Canadian passport holders can travel to many countries without obtaining any further documentation (such as visas) prior to taking the trip. A passport also functions as proof of citizenship, so a person holding a U.S. Passport is internationally recognized as a US citizen. In cases when visas are required, the visa stamps or stickers are placed on the pages of the passport. Border control officials will also stamp the pages of the passport with entry and exit stamps upon entering or exiting a country.