Bonfires are lit and there are fireworks displays all over London (and the UK) to commemorate the Gunpowder Plot, an attempt to blow up James I and his Parliament. The plot’s most famous conspirator, Guy Fawkes, (“The Guy”) is burned as an effigy. Although the official anniversary is on the 5th, bonfires and firework displays start up to 2 weeks before and go on for a week after the actual date. More details.