Solar particles follow Earth's magnetic field lines, which link the Northern and Southern Hemispheres. So when an aurora borealis lights up, an aurora australis often appears at the same moment on the other side of the globe, with a similar, mirror-like shape. Satellites have shown, though, that the twins are not always identical, depending notably on how Earth is tilted towards the Sun.
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.