We have a Carnival cruise booked in July 2013 and are trying to find the best excursions to take with our boys, ages 8 and 11. Snorkeling is an absolute must as well as visiting some cenotes, but the submersibles also sound intriguing, especially with an 8 year old. Which areas are the best for snorkeling to see the most variety of sea life? Which cenote offers the best location with the most diversity? What other excursions would you recommend for a family? Would a Carnival excursion be more appropriate or would you recommend an independent company? Any advice would be greatly appreciated! Thanks!!