The vast and perilous US-Mexico border
Stretching 3,000 kilometers from the Pacific to the Gulf of Mexico, the United States-Mexico border has become the epicenter of the migration policy debate in North America.
Tijuana and San Diego's walled beach
A large wall stretches into the Pacific Ocean at the beaches of San Diego and Tijuana, two populous cities separated by the US-Mexico border. It is one of the most secure areas of the frontier and is part of the 1100 kilometers (700 miles) of fencing that have been completed thus far.
Politically divisive
The fight over how to secure the border has divided Republicans, who support more fencing, and Democrats, who argue that using technology is more effective. Experts estimate it would cost $15-25 billion (€13-22 billion) to fully wall off the entire southern frontier.
The dangerous desert stretch
Large swaths of the border are covered in desert, desolate and uninhabited. Many migrants try to cross these areas, where they fall victim to disorientation, dehydration and where the risk of death is high. Activists often leave water (pictured) and other supplies to help migrants survive the dangerous trek.
The Rio Grande
Roughly half of the 3,000-kilometer border falls along the snaking Rio Grande. Migrants regularly attempt to cross the river, either by swimming or on rafts. The calm appearance of the Rio Grande is deceitful, as it is a fast-moving river with dangerous currents.
Crowded points of entry
The US-Mexico border is considered the most transited frontier in the world. Most of the movement takes place at the various points of entry, where lawful back-and-forth traffic and asylum-seekers meet. The Matamoros-Brownsville International Bridge (pictured) is one of 44 official points of entry and the last one before the border ends at the Gulf of Mexico.