Gunpowder
From Tardis Wiki, the free Doctor Who reference
Gunpowder was an explosive substance that was used mostly in warfare, such as cannons. This was used in cannons to explosively propel objects forward. It is usually used on Earth in ancient times, and on some primitive planets such as Ribos. (DW:The Ribos Operation)
One of the most notable use of gunpowder was in 1605, where Guy Fawkes and his anti-parliament regime blew up the Houses of Parliament. (MA: The Plotters)
