For the first time ever, travelers can join an expedition to the deepest spot in the oceans
https://edition.cnn.com/travel/article/marianas-trench-challenger-deep-dive/index.html
I've heard about hadal research from a professor who were doing research on it. He said crews of the submarine have to spend in the narrow space so long that they were told to defecate or urinate into a plastic bag. I don't know whether it's also true in this submarine for sightseeing.
