Watch the CBSN Originals documentary, "The Darien Gap: A Desperate Journey to America," in the video player above.

In 2017, the CBSN Originals team set out to cross the Darien Gap — a 60-mile stretch of virgin jungle that forms the border between Colombia and Panama. This fabled no-man's land has become a key section of the illegal migration corridor from South America to the U.S. border. It was our first stop in what would become a years-long effort to explore the untold stories behind the headlines of America's immigration debate.

Under the cover of the Darien's thick canopy, it's estimated tens of thousands of migrants from around the world brave the dangerous journey. Some pay smugglers, often referred to as "coyotes," a few hundred dollars to guide them through. Other options would be far easier — like taking a boat or plane into Central America, right up to the doorstep of the U.S. — but they heighten the risk of capture and immediate deportation.

During the physically arduous 10-day trek, a migrant from Iran named Shahab Shahbazi shared his story, telling us he was heading to the U.S. to escape religious persecution in his homeland. He was led by two local "coyotes" and carried just a small bag with a few items of clothing. Like many of the migrants the team encountered, he seemed hideously under-prepared for what lies ahead.

"I'm trying to find a life," he told CBS News. "I'm trying to find out if I can have a better life or not."

We parted ways at a Panamanian police outpost in the jungle. But when Shahab reconnected via a WhatsApp message three months later, the CBSN Originals team knew we had to return and follow the rest of his journey north.

Seeking Asylum

"Seeking Asylum: An Immigrant's Journey to America" chronicles Shahab's effort to gain entry into the U.S. through the asylum process, a legal route that offers protection to migrants fleeing persecution in their home countries. We reconnected with Shahab in Tijuana, Mexico, where he walked up to a U.S. border checkpoint to ask for asylum. He was placed in immigration detention for over six months, and then was released in San Diego to wait some more. This story traces Shahab's journey through a seemingly endless labyrinth that is the American immigration court system — including the role played by friends and allies.

Families in Crisis

"Families in Crisis: Illegal Immigration" follows Rafa, a man in El Salvador, who lived most of his life in the United States but was deported back to his birth country due to brushes with the law. He struggles to earn a decent living and is desperate to escape the violence in San Salvador, where he cares for his 5-year-old son Jacob. With his criminal record for theft, Rafa is the type of immigrant many Americans don't want in this country. Yet his son Jacob is innocent, caught up in a political fight he never asked to be a part of. Rafa is at a crossroads — contemplating ways to get Jacob into the U.S. to live with American relatives in safety, even if he has to break the law to do so. Through Rafa's conundrum, the complexities of the immigration debate and the revolving door of migration are shown in sharp relief.

Border Business

"Border Business: Inside Immigration" is the culmination of more than two years of in-depth reporting on the journeys of migrants seeking refuge in America. As desperate people struggle to get to the U.S., a sprawling network of individuals has sprung up to help them — and profit from them — all along the way. The fourth installment in the CBSN Originals migration series focuses on this cottage industry at work across Central America. Human smugglers, restaurant owners, activists, and immigration lawyers each play a role in getting people across the U.S. border and have come to depend on this human flow for their livelihoods.