Pachycereus

Pachycereus are a genus of giant columnar cacti, native mostly to Mexico and the southwestern United States. They are known for their great longevity and for having imposing and architectural forms.
They have very thick, branched, columnar stems, with a bluish-green color and long spines.
They grow mainly in the Sonoran Desert and the Baja California Peninsula. They form true "cactus forests" in arid zones and survive with little water and plenty of sun.