US-Mexico border wall will go along southern edge of Organ Pipe Cactus National Monument – an area of exceptional beauty.
United States President Donald Trump’s border wall has secured $1.3bn in funding, under a government spending package signed last week.
The barrier dividing the US and Mexico is well behind schedule, but it is breaking ground in Arizona, one of the most biologically diverse parts of the country.
The environmental cost of this may be irreversible.
Al Jazeera’s Rob Reynolds reports from near Sonoyta, Mexico.