Bulgarian cavers claim to have found an astonishing 50 km of new passage in the giant Ukrainian gypsum cave Optimisticeskaja. If true this puts it solidly in second place in the world long cave list, displacing South Dakota's Jewel Cave. <http://www.sofiaecho.com/article/bulgarians-mapping-europe-s-biggest-cave/id_29278/catid_70>
Mark Minton
