The trip is advertised to migrants as a secure VIP journey from the tourist-friendly Colombian island of San Andrés to Nicaragua. But in reality, it exposes desperate people to perilous conditions and a lucrative yet dangerous underworld. Hundreds have been rescued and dozens have vanished, but it's a chance many take to flee humanitarian crises in their own countries.

Since Venezuela's disputed election last month, government tactics to crack down on dissent using online surveillance and intimidation have escalated. Protesters say they are afraid and describe deleting online activity and hiding phones, while the government claims it has arrested some 2,400 people.