ARIZONA (REUTERS) - At 73, Mr Alvaro Enciso hikes into the hot Sonoran Desert in Arizona every week - he says, to be a voice for the voiceless.

With cross in hand, he treks through 100-degree heat, weaving through cactuses and desert brush.

When he gets to a spot where a migrant has died attempting to cross into the US from Mexico, Mr Enciso, an artist and an activist, plants his marker.

Each cross, he says, signifying the end of an American Dream.

"You know the Sonoran Desert has a secret," said Mr Enciso.

"Very few people know that 3,000 people here have died, that 2,000 people have disappeared. That is wrong."

This map published online by the humanitarian aid group Humane Borders is the inspiration behind Mr Enciso's mission.

The swarm of red dots representing the exact location of where a migrant body was found.

"I saw this map with thousands of red dots on it, you know, just one on top of the other... I want to go where those red dots, you know, the place where a tragedy took place," said Mr Enciso.

Mr Enciso, who left Columbia in the 1960s to attend college in the US, hopes his efforts will draw attention to migrant deaths and spur change to US immigration laws.

Under President Trump's administration, policies have been put in place to crackdown on illegal immigration.

They include his highly controversial "zero-tolerance" policy that separated hundreds of parents from their children at the US-Mexico border.

Trump abandoned the policy after a global outcry.

Said Mr Enciso: "We have broken the number one rule of what America is all about."

It's that belief that keeps Mr Enciso busy in his home workshop, nailing and painting crosses.

Using his skills as an artist to carry his message to the desert where Mr Enciso says for many, the American Dream ended before it ever began.