A scuba diver looks at an animal skull at Sac Aktun underwater cave system during exploration as part of the Gran Acuifero Maya Project near Tulum, in Quintana Roo state, Mexico February 12, 2014. Picture taken February 12, 2014. Jan Arild Aaserud/Courtesy Gran Acuifero Maya Project (GAM)/Handout via REUTERS ATTENTION EDITORS – THIS IMAGE WAS PROVIDED BY A THIRD PARTY. – RC12E2DA4710
