Over the weekend, James Cameron successfully made it to the the bottom of the Mariana Trench—the deepest point on Earth. Bad. Ass. 
 
 But also: lucky, brave, well-prepared, and maybe a little bit daft: Any number of factors could have turned the the veteran explorer-slash-director's epic adventure into his last act. 
 
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 The Mariana Trench is located in the western Pacific Ocean, to the east of the Mariana Islands. It's over 1,580 miles long, 43 miles wide on average, and and at it's deepest point—heroically known as Challenger Deep—it's an amazing 6.78 miles to the bottom. Almost 36,000 feet. Reaching those depths is incredibly dangerous, and James Cameron himself is alleged to have admitted that the mission offered "a lot of ways to die." So what could have gone wrong? 
 
 Implosion 
 
 The obvious, quickest, and most catastrophic route to failure. A weak spot in materials, a design flaw in the vehicle. Then, as the pressure increased—pop—the dive craft would have buckled. That doesn't mean drowning; it means James Cameron would have been squashed to death, with immense pressures of up to 15,750 psi turning his body into a James Cameron slurry. 
 
 Freezing 
 
 If the Deepsea Challenger, had somehow gotten stuck at the bottom of the trench, Cameron would have been relying on his life support systems to keep him alive. In terms of resources, he had 60 hours of oxygen—but far less in the way of power for heating. With the water of the Mariana Tench being a fairly consistent 0°C, he would have died of hypothermia long before he ran out of air. 
 
 Fire 
 
 The sub was packed full of technology and gadgetry—all requiring electricity. There was also a vast amount of pure O2 circulating around inside Deepsea Challenger. The tiniest of electrical faults or sparks, and that O2 would have had a fire burning hard and fast. There was a small fire extinguisher on board—but it might not have stood up to something major. 
 
 Melting 
 
 Even though the Mariana Trench is cold, it's surrounded hydrothermal vents—fissures in the Earth's surface from which geothermally heated water bursts, unannounced. Thing is, that water is incredibly hot—700°C to be precise. That's hot enough to melt the submarine's view port. Then Cameron would have had water issuing into his craft, driven by 15,750 psi of pressure. Game over. 
 
 Entanglement 
 
 
 
 
 
 Though you might not realize it, the sea bed—even the area surrounding the Mariana Trench—is littered with submarine communication cables. They're there to string together telecommunication systems around the globe, but also turn the bottom of the sea into an assault course for submariners. If Cameron had gotten tangled in one of those lines, he would've struggled to make it back to the surface. 
 
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 Fortunately, Cameron was one lucky mother; he managed to make it down and back up without a hitch. Which is fortunate for us, because no doubt his footage from the alien-esque world of Challenger Deep is going to be freakin' amazing. Congratulations, James. 
 
 Image by Mark Thiessen/AP ||||| Filmmaker James Cameron surfaced three hours earlier than planned Monday after hydraulic fluid started leaking in his sub, as he became the first adventurer to make a solo journey to the deepest point on the ocean’s floor. 
 
 The 57-year-old described diving to a depth of nearly 7 miles in the 12-ton Deepsea Challenger as a “heckuva ride” after resurfacing in the Pacific Ocean, 300 miles southwest of Guam, on Monday morning. 
 
 He said, “It was bleak. It looked like the moon. I didn’t see a fish… I didn’t find anything that looked alive to me, other than a few [shrimplike] amphipods in the water. 
 
 “I didn’t feel like I got to a place where I could take interesting geology samples or found anything interesting biologically,” he added. 
 
 The “Titanic” and “Avatar” director had planned on spending six hours on the ocean floor collecting samples and sent a tweet after reaching the Challenger Deep undersea valley in the Mariana Trench. 
 
 “Just arrived at the ocean’s deepest [point]. Hitting bottom never felt so good. Can’t wait to share what I’m seeing [with] you,” Cameron said in the tweet. 
 
 The descent took 156 minutes, but after he noticed the fluid leak Cameron decided to end the mission early and his ascent took just 70 minutes. 
 
 His sub was spotted by helicopter and he was picked up by the support vessel the Mermaid Sapphire shortly afterward. 
 
 He said, “I saw a lot of hydraulic oil come up in front of the port. The port got coated with it. I couldn’t pick anything up, so I began to feel like it was a moment of diminishing returns to go on. I lost a lot of thrusters. I lost the whole starboard side. That’s when I decided to come up. I couldn’t go any further — I was just spinning in a circle.” 
 
 Cameron hinted that he could carry out another dive to the trench in the future. He said, “Next dive. Gotta leave something for the next one.” 
 
 Others paid tribute to his bravery. 
 
 “@JimCameron has surfaced! Congrats to him on his historic solo dive to the ocean’s deepest point,” said organizers of his mission, Deep Sea Challenge, at 10:03 p.m. ET Sunday. 
 
 Arnold Schwarzenegger, who was directed by Cameron in the “Terminator” films, was among the first to congratulate Cameron, tweeting, “Congrats to my great friend on the deepest solo dive ever. Always a pioneer.” 
 
 Cameron embarked on the solo trip in a sub that he has described as a “vertical torpedo,” outfitted with 3D cameras and a tower of LED bulbs to capture video footage of the alien world, some 35,800 feet below the surface. He also collected samples. National Geographic will chronicle the adventure in 3D at theaters and later on TV. 
 
 In addition to studying deep ocean science, he had been training for the physical challenges of the mission — running several miles a day, practicing yoga and preparing to deal with the sub’s cramped quarters. 
 
 No one has been to Challenger Deep since Jacques Piccard and Don Walsh made the descent in a 1960 expedition for the US Navy. Their stay only lasted about 20 minutes and did not allow for the type of extensive study that Cameron planned.
– James Cameron's trip to the world's deepest spot sounds a wee bit like something of a disappointment. The six hours he intended to spend at the bottom of the sea—filming and gathering geology samples—was cut in half when hydraulic fluid started leaking in his submersible. As for his time at the bottom, "I didn't see a fish ... I didn't find anything that looked alive to me, other than a few amphipods in the water," he says. "I didn't feel like I got to a place where I could take interesting geology samples or found anything interesting biologically," he noted, according to the New York Post. It took him 156 minutes to go down, but only 70 minutes to come back up after he spotted the leak. "The port got coated" with oil, he said, noting that he lost control of the starboard side of the sub. "That's when I decided to come up. I couldn't go any further—I was just spinning in a circle." But it sounds as though he's planning to go down again: "Next dive. I gotta leave something for the next one," he said. (But hey, at least he's alive. Gizmodo rounds up five ways he could have perished, and they don't sound fun.)