Every drop seeping from the ceiling of a limestone cave leaves behind a minute film of calcite as it loses carbon dioxide. Stalactites typically grow on the order of 0.1 mm a year, about a centimetre per century, though rates vary widely. A column a few metres tall can thus represent tens of thousands of years of patience. Touching them can be enough to halt their growth.
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.