Signed on May 6, 1882.
The law also placed restrictions on Chinese who were already in the US, forcing them to obtain certificates in order to re-enter if they left the country and banning them from securing citizenship.
The act expired in 1892 but was extended for a further 10 years in the form of another - the Geary Act. This placed additional restrictions on Chinese residents of the country, forcing them to register and to obtain a certificate of residence, without which they could be deported.
This changed in 1943 with the Magnuson Act - which allowed some Chinese immigration and for some Chinese already residing in the country to become naturalised citizens, but which maintained the ban on property and business ownership. This came at a time when China was a US ally during World War II.
As millions of people became refugees during World War II, US President Franklin D Roosevelt argued that refugees posed a serious threat to the country's national security. Drawing on fears that Nazi spies could be hiding among them, the country limited the number of German Jews who could be admitted to 26,000 annually. And it is estimated that for most of the Hitler era, less than 25 percent of that quota was actually filled.
Signed on March 3, 1903.
Following the 1979 Iranian hostage crisis, during which the US embassy in Tehran was stormed and 52 Americans were held hostage for 444 days, American President Jimmy Carter cut diplomatic relations with and imposed sanctions on Iran. He also banned Iranians from entering the country.