Mention James Cameron and the first thing most people probably think of is Avatar, or perhaps the 1997 mega-blockbuster, disaster / romance mashup Titanic. Most people probably don't think of him as a world record-setting submarine diver — but after an expedition Cameron made on Tuesday, that's exactly what he is. The filmmaker took his custom deep-sea submarine, the Deepsea Challenger, deeper than any other human has ever gone on a solo mission — 5.1 miles straight down, in fact. It turns out Cameron's just getting started: next, he plans to reach the Mariana Trench's Challenger Deep, a place so deep that humans haven't visited it in over 52 years. It turns out that after filming Titanic, Cameron became quite an avid diver and has spent the better part of the last 10 years on deep-sea exploration.

Thanks to the massive technology upgrades that have taken place since 1960, Cameron will get to spend about six hours on the ocean's floor, compared to only 20 minutes spent by the earlier expedition. Naturally, the entire expedition will be filmed: the 24-foot tall submarine has been outfitted with numerous 3D high-definition cameras and an eight foot tall array of LED lighting. There's a lot of other technology on board that's more focused on keeping passengers alive than documenting anything — due to the 16,000 pound-per-square-inch pressure that exists at the bottom of the ocean, the submarine will actually compress by about two and a half inches during the planned 6.8-mile decent. National Geographic has an in-depth look at Cameron's planned voyage, so check it out if you're interested in learning more about one of the earth's final frontiers.