Guam - Hollywood Filmmaker James Cameron says he will make the historic dive down to Challenger Deep today, Sunday, Guam time. On twitter at around 10:30am Cameron wrote "I only tweet when I have something worth saying. Today is the culmination of a 7 yr project. It's finally dive day."  In a lime green submersible he helped design, it will take an estimated two hours for Cameron to reach the bottom of Challenger Deep in the Marianas Trench. Once he reaches the bottom he will spend about six hours taking samples for scientific research as well as shoot 3D video for one of his upcoming projects, a National Geographic TV special and a documentary. Only one other person alive has dived the Challenger Deep and is part of Cameron's expedition team, Don Walsh. Cameron has several partners in this historic mission, including National Geographic, Telstra and Rolex. You can follow the latest on the project by logging on to www.deepseachallenge.com.