Every year, thousands risk the journey to improve their lives or flee the violence in their home countries.
Many migrants never make it across.
Over the years, thousands have gone missing, leaving their families searching for clues online of what went wrong.
A spokesperson for the group says that tens of thousands of people have disappeared since the 1990s. More than 6,000 people have been found dead over the past 16 years attempting to enter the US from Mexico along the desert, according to US border patrol agents.
These migrants face potential risks from their smugglers, US border patrol agents, kidnappers, armed American anti-immigration activists and lethal snakes, spiders and scorpions. They could also die from dehydration in a desert that reaches 110°F (43°C).