Groups of families, including many young people and small children escaping violence, poverty and persecution in Central America, are not a new phenomenon.
For several years, people have fled Honduras, El Salvador, Guatemala and other countries to head north towards the USA.
Travelling as a group, many make the exhausting and dangerous journey through Mexico. Some travel with their children. Many have the aim of seeking protection as refugees in the USA or in Mexico.
However, the climate towards migrants and refugees has deteriorated sharply under the Trump administration, which has separated children from asylum-seeking parents, threatened to close the southern border to Central Americans and proposed paying the Mexican government millions of dollars to deport irregular migrants, among other hostile policies.