Dos Ojos lies north of the rest of the Sac Actun cave system. As a separate system, Dos Ojos remained in the top ten, if not the top three, longest underwater cave systems in the world since the late 1980s. Dos Ojos contains the deepest known cave passage in Quintana Roo with of depth located at "The Pit" discovered in 1996 by cave explorers who came all the way from the main entrance some away. The deep passages include the "Wakulla Room", the "Beyond Main Base (BMB) passage", "Jill's room" and "The Next Generation passage". In August 2012 Dos Ojos was connected through a dry passage to Sistema Sac Actun. With March 2014 the total length of the combined system measures .