My mom's worst fear is drowning, and I think that's fair. Being submerged in water and being totally aware you can't breathe has to be terrifying.
For two British sailors in 1973, they had to endure something almost as bad, if not worse. Pilot Roger Chapman and senior pilot Roger Mallinson were on board Pisces III, in a deep-sea submersible, a type of submarine. Things went wrong, and the two sailors were left stranded 1600ft at the bottom of the Atlantic Ocean for three days.
Here's what happened, and how they survived.
Chapman and Mallinson were tasked with completing a routine dive to lay transatlantic telephone cable on the ocean floor.
"It took about 40 minutes to sink down to not far off 1,600ft (500m) and a bit faster to get back up," says Chapman. "We'd do eight-hour shifts, going along the surface of the seabed at half a mile an hour, setting up pumps and jets which liquefied the mud, laying cable and making sure it was all covered. It was very slow, murky work."
Mallinson had just come off a 26 hour shift, so he was already exhausted. It turns out the Pisces III had required some repairs, and while he was fixing it Mallinson decided to change the oxygen tank.
"It was quite ample to run the dive, but for some reason I decided to change it to a full one, which was no mean physical feat as it was very heavy," the sailor said. "I could have got into trouble for changing a half used bottle, but as it happens, if I hadn't, we wouldn't have lived."
The two pilots kept a video diary of their mission for records, and that's how they managed to share their experience of being trapped at the bottom of the sea.
Continue reading to find out how the two sailors were literally swallowed by the ocean floor, and how they managed to survive.