In 1973, a Mexican anthropologist named Santiago Genovés assembled a group of people from different countries, religions and cultures to cross the Atlantic on a raft with minimal comforts, no motor and a single sail. He was hoping to observe conflict and even violence, but it didn’t turn out the way he’d anticipated. We talk to filmmaker Marcus Lindeen about his documentary, The Raft about the original journey—and the reunion 43 years later.