In Canada's Bay of Fundy, the difference between high and low tide can reach about 16 m, a world record. The bay's long, funnel-like shape makes the water slosh in resonance with the tide, amplifying it. At low tide, boats sit stranded on the seabed where, a few hours earlier, the water stood as high as a five-storey building.
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.