The largest jellyfish in the world is considered to be the leviathan jellyfish (Cyanea capillata), which can reach a diameter of up to 2.5 meters and have tentacles up to 30 meters long. These jellyfish live in the cold waters of the Arctic Ocean and can be dangerous to humans because of their large size and the venom they emit. However, not all leviathan jellyfish are so large, their size may vary depending on the habitat conditions.
