A potentially "immortal" jellyfish species that can age backward—the Benjamin Button of the deep—is silently invading the world's oceans, swarm by swarm, a recent study says.. Like the Brad ...

In other parts of the world, swarms of jellyfish have menaced swimmers and clogged fishing nets. In 2006, beaches in Italy and Spain were closed because of a bloom of jellyfish known as mauve ...

National Geographic's Pictures of the Year showcase "the wonder of our world in 29 pictures," and features work by photographers around the world. From a lion's mane jellyfish in the Arctic ...