Every day, nearly 3,000 dugout canoes cross the Oyapock River, which serves as a natural demarcation in South America between Brazil and French Guiana. The river's banks are the scene of trafficking, illegal immigration and unlawful gold panning. Locals play cat and mouse with the border police, who try their best to monitor the comings and goings. The Covid-19 pandemic should have meant a hermetic closure of the border. Instead, it showed more than ever how uncontrollable this frontier is. FRANCE 24's Fanny Lothaire and Laura Damase report, with Séverine Bardon and Olivier Marzin.