Filmmaker and National Geographic Explorer-in-Residence James Cameron announced today that he will attempt to reach the world's deepest point, the Mariana Trench, nearly 7 miles (11.2 km) beneath the ocean?s surface, in the coming weeks. Cameron?s dive in his specially designed submersible marks the launch of "Deepsea Challenge", a joint scientific project by Cameron, the National Geographic Society and Rolex to conduct deep-ocean research ...