Homeland Security Secretary Kristi Noem says the entire southern border wall with Mexico is being painted black to deter illegal immigration.

Using black paint to make the entire US-Mexico border wall hotter and harder to climb was reportedly the president's idea.

Secretary credits President Trump with the idea, citing black paint's ability to make the metal hotter in the sun. Homeland Security Secretary Kristi Noem announced on Tuesday that the entire border wall along the U.