Colombian police scour the streets looking for undocumented migrants. All of them are Venezuelan, selling whatever they can. Water, work, sex. The officers enter a nightclub and round up more than 30 prostitutes. Jocelin, that’s her working name, wants me to see a picture of her nephew back in Venezuela. She tells me he died of malnutrition a month ago. She’s hiding her face from the camera because her husband and three children don’t know how she pays for the food they eat. They think she’s in Colombia waiting tables. I’m here in the border town of Cúcuta as Venezuela prepares to hold its first presidential election since Nicolas Maduro took power and began silencing his opposition, and since the country’s oil-based economy collapsed. It caps a year in which hundreds of thousands fled the country. And so I thought if people can’t speak freely inside Venezuela perhaps they would here, once they cross over the border into Colombia. But I quickly find that people aren’t thinking about the election. They’re just trying to survive. The Simón Bolívar International Bridge is the busiest point of exodus for Venezuelans. But it’s not a one-way street. Thirty-five thousand march across each day, often going back and forth, to buy basic things they can’t get or afford in their country like rice and toilet paper. A shortage of medical supplies has hundreds of women coming over just to have their baby. But more and more Venezuelans crossing are just looking for a new start somewhere else. With so many Venezuelans pouring in, the Colombian government stopped issuing temporary visas, and this has made it harder for refugees to earn a living here. Those fortunate to have passports and enough cash travel on to other countries where they hope to find jobs. The less fortunate scramble. And rumors are flying. A popular one is that Americans are paying for bus tickets to other South American countries. I’m filming at the bridge one day when a woman comes up to ask if we’re the Americans giving out aid. Yuliana and Ivan took a 14-hour bus ride on a leap of faith that this rumor was true. Until a year ago, they were still O.K.: a comfortable middle-class family in Venezuela. Then, out-of-control inflation made living so expensive, they were down to one meal a day. And then they lost their apartment. Now they’re homeless on the street with a baby and no prospect for work. Once over the bridge, they’re hit by the chaos of this place known simply as la parada, the stopping place. It’s an unfortunate but apt description of what happens to many families who flee, only to find themselves stuck here. Like Hector Mendoza: He left his farm in Venezuela when he could no longer find the seeds, chemicals or tractor parts he needed to keep it going. He arrived in Cúcuta three months ago with his pregnant wife and two kids. They’ve been camping near the central plaza for two months, surviving on a diet of junk food and handouts. He makes small change holding places in the long line for Western Union. At night his family beds down on sheets of cardboard. Mildred Rosales is trying to buy her teenage daughter a bus ticket to Peru. She’s selling her wedding ring to do it. Just outside the jewelry shop, another family says goodbye. This time it’s the mother who’s leaving to Peru. Her son Yershey walks back to Venezuela with his aunt and uncle. Their plan is to keep saving money until they can afford to send someone else. If President Maduro solidifies his grip on power and his country of about 30 million continues to suffer from crime and poverty, an even larger exodus may be coming. What happens in Venezuela could destabilize the entire continent.