25. A family of people with blue skin lived in Kentucky for many generations. The Fulgates of Troublesome Creek are thought to have gained their blue skin through combination of inbreeding and a rare genetic condition known as methemoglobinemia.

26. Powerful earthquakes can permanently shorten the length of Earth's day, by moving the spin of the Earth's axis. The 2011 Japan earthquake knocked 1.8 microseconds off our days. The 2004 Sumatra quake cost us around 6.8 microseconds.

27. The first American film to show a toilet being flushed on screen was Alfred Hitchcock's Psycho.

28. Melting glaciers and icebergs make a distinctive fizzing noise known as "bergy seltzer".

29. There is a glacier called "Blood Falls" in Antarctica that regularly pours out red liquid, making it look like the ice is bleeding. (It's actually oxidised salty water.)

30. In 2008 scientists discovered a new species of bacteria that lives in hairspray.

31. The top of the Eiffel Tower leans away from the sun, as the metal facing the sun heats up and expands. It can move as much as 7 inches.