Final answer:
Most people carry a passport during international travels, which confirms their identity and nationality for entry or exit from a country. The U.S. requires a valid passport for all citizens traveling internationally based on the Immigration and Nationality Act of 1952. Earlier forms of passports include the Mongol paiza for safe passage.
Step-by-step explanation:
The special document that most people carry during international travels is a passport. Passports serve as official travel documents that are widely recognized for international travel and are used to authenticate the bearer's identity and nationality, thereby granting them permission to travel to and enter other countries. Conditions for obtaining a passport can vary, with certain restrictions possibly applied if a person is under criminal investigation, on a terrorist watch list, or part of a group that is disfavored by their government, such as the case of the Uyghurs in China.
In the United States, the Immigration and Nationality Act of 1952 requires all US citizens to have a valid passport to leave or enter the country. The importance of a passport dates back to historical documents such as the paiza, an early form of passport used by Mongol diplomats for safe passage.
However, some individuals may have different views on what constitutes an important document based on their cultural or social affiliations. While U.S. citizens might consider the Constitution vital, indigenous people may give more weight to treaties.