In this photo provided by National Geographic, filmmaker and National Geographic Explorer-in-Residence James Cameron slides into the hatch of the DEEPSEA CHALLENGER submersible as he prepares for his record dive to the bottom of the Mariana Trench, Sunday, March 25, 2012. The dive was part of DEEPSEA CHALLENGE, a joint scientific expedition by Cameron, the National Geographic Society and Rolex to conduct deep-ocean research. (AP Photo/National Geographic, Mark Thiessen) MANDATORY CREDIT
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