A single issue has dominated the US-Mexico relationship in recent years: immigration.
For President Donald Trump, that is roughly the only lens through which the White House views its relationship with its neighbor to the south.
Now, under President Joe Biden, immigration remains a priority as record numbers make the journey north, often expecting entry into the US to be easier than before.
Recently, thousands of migrants from across Latin America have tried to make the trip as a single group.
BBC reporter Will Grant met them while they were traveling.
