Manatees glide through warm waters in and around Three Sisters Springs in Crystal River, Florida, a winter shelter from colder ocean temperatures. In the heart of Florida's Gulf Coast lies one of the only places in the world where humans are encouraged to interact with these curious creatures. The practice has been controversial, but permission to swim with the animals predates the Endangered Species Act of 1973. Hundreds of manatees, at great risk of being hit by boats elsewhere, congregate in this protected, shallow, jade green lagoon. In this short film from Dive Documentaries, tour operator Captain Broderick highlights the correct way to observe the creatures in their natural habitat. Read about protecting manatees in Three Sisters Springs. voices.nationalgeographic.com/2014/08/23/the-last-spring-protecting-floridas-manatees/ See more from filmmaker Jason Boone. www.divedocumentaries.com/ www.boonedocumentaries.com/ The Short Film Showcase spotlights exceptional short videos created by filmmakers from around the Web and selected by National Geographic editors. We look for work that affirms National Geographic's mission of inspiring people to care about the planet. The filmmakers created the content presented, and the opinions expressed are their own, not those of the National Geographic Society. Know of a great short film that should be part of our Showcase? Email SFS at ngs dot org to submit a video for consideration.