Sharks have been around for at least 400 million years, even before dinosaurs walked the earth. These apex predators have a reputation for attacking all sorts of marine life, which sometimes includes the occasional human. But are sharks a danger to people or are people a danger to sharks? CNN's Boris Sanchez is an experienced diver, and over the next hour he takes us under water with sharks to show us both the beauty and danger of these creatures. Learn more about your ad choices. Visit podcastchoices.com/adchoices