Modern Marvels: Halloween

Candy is America's sweetest guilty pleasure. Find out the ingredient that gives Lemonheads their sour punch, the substance that puts the polish on Mike and Ikes, and more mouth-watering confectionery secrets.

All it takes to set off a booby trap is an unsuspecting victim and a harmless-looking object. Explore their history, from the ancient Egyptians, Chinese, Greeks, and Romans to the modern War on Terror.

Designed like defensive machines, medieval castles represented the perfect fusion of form and function. Journey back to that unruly era to examine the complexity of their construction and many uses.

More than 2 million people die in the U.S. each year. That works out to about 5,500 burials a day. Take a look at dealing with the dead throughout the centuries - and at today's $20 billion funeral industry.

Explore the tech developed to create and respond to doomsday threats ranging from very real (nuclear arsenals) to controversial (global warming) to futuristic (nanotechnology, cyborgs, and robots).

Examine more threats - both natural and man-made - that may endanger civilization. From the far reaches of space to tiny viruses, doomsday sources are many, but so are technologies used to keep the chaos at bay.