BBC - History - Red Sky at Night

Not that we don't have enough contemporary disaster to think about just now, but (as the Scotsman.com's Business News e-mail's Fact of the Day reminds me) it was on September 2, 1666, that the Great Fire of London started. The BBC has extensive information and links in its history web section.

More:
Wikipedia: Great Fire of London
The Great Fire of London - 1666, presented by London Fire and Civil Defence Authority in association with AngliaCampus.
Samuel Pepys Diary 1666 - Great Fire