A man has made the deepest ever dive by a human inside a submarine—only to make the troubling discovery of plastic trash resting on the ocean floor. Victor Vescovo, a retired naval officer who is now an investor, made the descent into the Pacific Ocean’s Mariana Trench on Monday and traveled down 35,853 feet from the surface—52 feet lower than the previous record, which has been held since 1960. He found manmade material on the ocean floor that he believes to be plastic, though the object is now undergoing tests to confirm that. It was just the third time humans have managed to dive to the deepest point in the ocean on earth. Director James Cameron was the last to visit in 2012 in his submarine, reaching a depth of 35,787 feet.