Tens of millions of years ago, much of the Amazon basin drained west, towards the Pacific. The rise of the Andes gradually blocked that route, first creating a vast system of lakes and wetlands. Around 10 million years ago, the river finally broke through to the east and began emptying into the Atlantic, as it does today.
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.