An Aglantha digitale (pink helmet jellyfish), a young Lion’s Mane jellyfish (Cyanea capillata), and a Lion’s Mane jellyfish at the end of its life cycle in the White Sea. #NatGeoExplorer Alexander Semenov (narwhal_season) hopes to draw attention to the Arctic seas' unique beauty and fragile ecosystems through unfamiliar animals that live in the chilling depths. "You always want to protect more of what you know and love, what you admire. As long as the Arctic seas are just huge cold masses of water to most people, no one will even care that there is anything to protect," Semenov explains of his mission. #WorldJellyfishDay Photos by Alexander Semenov