Sound travels about a kilometre every three seconds: count the seconds between flash and thunder, divide by three, and you get the distance in kilometres. Thunder can usually be heard up to around 15 km away. Lightning can strike a similar distance from the storm, sometimes out of a still-blue sky. So if you hear thunder, you are within range.
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.