▁from ▁the ▁UK ▁and ▁the ▁US , ▁ 1 1 ▁were ▁cave ▁div ing ▁using ▁closed ▁cycle ▁life ▁support ▁systems ▁called ▁re bre athers . ▁They ▁expl ored ▁three ▁parts ▁of ▁the ▁sum p ▁system ▁and ▁discovered ▁an ▁up stream ▁tunnel ▁leading ▁to ▁the ▁only ▁known ▁exit ▁for ▁the ▁water ▁that ▁enters ▁the ▁Hu aut la ▁c aves , ▁the ▁spring ▁of ▁Pe ña ▁Color ada . ▁During ▁a ▁two - month ▁expedition ▁in ▁ 2 0 1 3 ▁involving ▁ 4 0 ▁team ▁members ▁from ▁the ▁UK , ▁USA , ▁Canada , ▁Poland ▁and ▁Mexico , ▁ca vers ▁entered ▁through ▁S ót ano ▁de ▁San ▁Ag ust in ; ▁it ▁took ▁divers ▁three ▁weeks ▁to ▁reach ▁" what ▁looked ▁like ▁a ▁calm , ▁rock - en closed ▁lake ▁about ▁ 1 0 0 ▁feet ▁wide ", ▁the ▁San ▁Ag ust ín ▁sum p . ▁One ▁of ▁them ▁established ▁a ▁new ▁record ▁depth ▁when ▁stopping ▁at ▁ 1 5 4 5 ▁meters . ▁The ▁new ▁survey ▁data ▁gave ▁the ▁cave ▁a ▁total ▁length ▁of ▁ 6 4 . 2 ▁kilom eters . ▁A ▁navig able ▁connection ▁between ▁where ▁water ▁enters ▁S istema ▁Hu aut la ▁and ▁where ▁it ▁ex its ▁at ▁Pe ña ▁Color ada ▁has ▁yet ▁to ▁be ▁found . ▁ ▁Since ▁then ▁consecutive ▁annual ▁exped itions ▁have ▁been ▁launched ▁as ▁part ▁of ▁the ▁Pro yect o ▁Es pe le ológ ico ▁S istema ▁Hu aut la ▁( P ES H ). ▁ ▁Ge ology ▁S istema ▁Hu aut la ▁is ▁a