Mexico's Border

http://www.vice.com/Fringes/mexicos-other-border
When people speak about Mexico's border, they immediately think of the US-Mexico one.  The reality is that most of the people that come into the US illegally are from Central America. People tend to ignore the fact that Mexico has a southern border that almost all of the Central Americans use to eventually get to the US.  At this border, like the northern border of Mexico, people cross illegally because they do no have the proper documentation.  This means the trip is twice as hard for those people, because they have to make this dangerous and illegal border crossing twice (once into Mexico, then into the US).
Most of the people who make this journey are honest and hardworking, who only do so because the have family they need to support and have no other option.  Just getting into Mexico can get the traveler into sticky situations such as extortion, kidnapping, forced to be drug mules, but mostly sexual exploitation for women travelers.  Some women simply get stuck in prostitution and end up staying in these small towns. It got so bad that in Mexico, they setup a special federal division to prosecute crimes against migrants.
The end result is a flood of Central American immigrants in Mexico, especially between 2005 and 2009.  This raises the ability of the cartels and gangs to use these migrants as pawns/victims of their organizations.  Prostitution levels are rising, as well as sex trafficking and violence.