For centuries, accounts of walls of water appearing from nowhere were met with scepticism. On 1 January 1995, sensors on the Draupner oil platform in the North Sea recorded a wave about 26 m high, in seas where other waves topped out around 12 m. It was the first instrumental measurement of a rogue wave, now a full-fledged field of research.
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.