Earth's axis is tilted about 23.4°, and that angle shifts by only two or three degrees over tens of thousands of years. According to simulations published in Nature in 1993, this is largely thanks to the Moon. Without it, the tilt could swing chaotically over a wide range, upending the seasons, as has probably happened on Mars.
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.