For centuries, sailors have described nights when the ocean glows white all the way to the horizon. The leading explanation is billions of bioluminescent bacteria. In 2005, researchers first spotted the phenomenon in satellite images, and a 2019 event off Java covered more than 100,000 km², glowing for over a month.
On 27 August 1883, the eruption of the Indonesian volcano Krakatoa was heard as far away as Rodrigues Island, nearly 4,800 km away. Its pressure wave was picked up by barometers worldwide and circled the globe several times. The tsunamis that followed killed more than 36,000 people.
The deepest known point in the ocean, Challenger Deep, lies roughly 10,900 m below the Pacific surface. Drop Everest in and its summit would still sit about 2 km underwater. Down there, the pressure is more than 1,000 times what you feel at sea level, roughly a tonne pressing on every square centimetre.