In the 1930s, during the Great Depression, over a million people of Mexican origin were driven out of the US, forced to head south for Mexico.
It was called the "Mexican Repatriation" and it aimed to keep jobs for "real" Americans.
Seventy years on there are fears that history could repeat itself.
In Crossing Continents, Linda Pressly travels to California to meet some of the people who were expelled in the 1930s and who have since returned, and hears how attempts are now being made to uncover the extent of what has been called "unconstitutional deportation".
The details of this event are emerging at a time when there are growing fears about the levels of illegal immigration into the United States.
The community of Escondido, north of San Diego, has just passed a law to ban landlords from renting property to illegal immigrants.
Marie Waldron, the councillor behind the move, and her supporters, claim they are so frustrated by the lack of Federal Government action to stem the tide of immigration, they have been forced to take matters into their own hands.
The law is being challenged in the courts but already people are packing their bags and there is a tangible feeling of fear amongst the Latino community.
Since Escondido passed the rental ban law a month ago, many other towns across the US are considering introducing something similar.
And as Ms Waldron told Crossing Continents "little fires are starting all over our country trying to take on this issue".
Crossing Continents was broadcast on Thursday, 30 November 2006, at 1102 GMT and was repeated on Monday, 4 December 2006, at 2030 GMT.
Presenter: Linda Pressly
Producer: Emma Rippon
Editor: Sue Ellis