The shape of Earth's orbit, the tilt of its axis and the direction that axis points all vary in cycles of roughly 100,000, 41,000 and 23,000 years. These Milankovitch cycles change how sunlight is distributed across seasons and latitudes. In 1976, an analysis of ocean sediments confirmed that they pace the alternation of ice ages and warmer periods over roughly the last million years.
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.