Relative calm follows rioting, chaos in Baltimore
Curfew, state of emergency declared as 200 arrests made; National Guard deployed; firefighters dousing still-simmering blazes
Baltimore mayor defends delay of response to riots
Maryland National Guard rolled into Baltimore in midst of violent protests, but city's response left many wondering what took so long
Fears Nepal quake toll could more than double
Full scale of Himalayan disaster to come clear as crews helicopter into remote villages near epicenter
Why not charge for GPS?
Colonel William Cooley explains why the U.S. Air Force provides GPS satellite signals free of charge to the entire world.