Here's one for the nightmares

Grim WaPo story that points out that terrorists face challenges with biological weapons but, as the paragraphs I've quoted show, they're making inevitable progress:

But specialists also say it is all but inevitable that al Qaeda or another terrorist group will gain the expertise to launch small-scale biological attacks and eventually inflict mass casualties. Information on the mechanics of creating bioweapons is easily accessible on the Internet and in technical manuals, and the equipment to do the job is readily found. Many brew pubs, for example, have fermenters that can cook up deadly germs. Advances in bioscience, and the rapid dissemination of this knowledge worldwide, are making it easier for even undergraduates to create dangerous pathogens. Creating microbe weapons is more challenging than producing the simplest implements of terrorism -- conventional explosives or chemical weapons -- but much less difficult than the most technically daunting -- nuclear weapons -- experts say.

Having read the book about the absolute horror of the Spanish Influenza in 1918, and being enough of a history buff to be familiar with the great epidemics in world history, biological weapons have always frightened me. And it's no consolation to know that the terrorists are completely in synch with long-standing attempts at biological warfare. Hundreds of years ago, soldiers besieging towns and castles tried to hasten events by hurling diseased corpses over the walls.