Cave Diving in Dan's Cave and Ralph's Cave, Abaco, Bahamas. For a trip report, have a look at: http://www.advanceddivermagazine.com/articles/crystal/crystal.html  All video was shot with a Sony Z7U and a Z1U with Amphibico housings and various video lights from Amphibico and Light Monkey.  WARNING! Cave diving can be an extremely dangerous activity, resulting in serious injury or death.  Never, ever venture into an underwater cave without the proper training and equipment.