Largest known underwater cave on Earth discovered in Mexico; holds clues to Mayan civilization
A scuba diver takes a look at an animal skull at Sac Aktun underwater cave system throughout expedition as part of the Gran Acuifero Maya Project near Tulum, in Quintana Roo state, Mexico February 12,2014 (JanArild Aaserud/CourtesyGran Acuifero Maya Project [GAM]/Handout through REUTERS) A group of professionals in Mexico has discovered 2 connected underwater caverns…