666 is, of course, the mark of the beast, and on this day in 1666 Londoners were already feeling anxious. The city had been decimated by an outbreak of plague, which began the year before and continued well into spring.
And then - as every English schoolchild learns - late at night a fire started in a bakery in Pudding Lane. It didn't look too serious to begin with - in one of history's more unfortunate statements, the Mayor of London observed that "A woman might piss it out!" - but the city was wooden and dry. The fire raged for three days, destroying 80% of London, including 13,200 houses, 87 churches and St Paul's Cathedral.
On the plus side, it did help put an end to the bubonic plague, while only six people are known to have died. There was no fire department in those days - although citizens did their best with fire breaks - so today's anniversary is a great opportunity to toast firemen everywhere with a splendid Rum Sour, the Fireman's Sour.