The Hartford Police Department is one of a number of police departments across the country that are offering up their parking lots as "safe zones" for Craigslist transactions. Courtesy of the Hartford Police Department hide caption

itoggle caption Courtesy of the Hartford Police Department

The Havana studio of prominent artist Kcho is ringed by Cubans with their heads buried in screens. Users say the only other free Internet connection in Havana is at the U.S. Interests Section. Eyder Peralta/NPR hide caption

itoggle caption Eyder Peralta/NPR

Continuous Liquid Interface Production, or CLIP, uses liquid resin with ultraviolet light and oxygen projected through it to create more complex structures than those of existing 3-D printers. Nina Gregory/NPR hide caption

itoggle caption Nina Gregory/NPR