You know going to the beach is a wonderful get-a-way for the family! The sun, the sand, the ocean right at your back door....ahhhhh, paradise. Really? This is in the ocean! Divers have now swum with a huge barrel jellyfish off the coast of Cornwall. Lizzie Daly, a biologist with Wild Ocean Week, said the creature was as big as her body. It is the largest species of jellyfish which is found in British waters, with the average diameter being about 40cm (16 inches). OK, I'll stick to the waters of the Great Lakes! Image by underwater cameraman Dan Abbott.