The world's first 3D-printed neighborhood now has its first houses

In Memphis, a creative blight-reduction initiative called 25 Square Blocks broke down the city into blocks. Inspectors were able to quickly identify all the violations and fix them, using the same amount of funding, but less time, as the old call-and-respond model.

Farmers in Vietnam face rising sea levels but rejected the city's water engineering projects. They prefer gradual measures to cope with climate change so scientists have allowed the farmers to steer the conversation.

Louisiana and Vietnam both need affordable solutions to rising sea levels. Leaders from Vietnam visited Louisiana to compare ideas.

Most insurance companies avoid insuring poor farmers because the transaction costs are too high, but a non-profit in Kenya created a sustainable way to cover them.

The non-profit Root Capital created a lending initiative in Mexico which helps mid-size rural farmers gain access to capital, skills, and consumer markets from which they would otherwise be excluded.

As a state with robust populations of wildlife, Montana has had its share of roadkill. Its Department of Transportation developed animal shelving, a type of wildlife crossing, to enable safe passage for small animals who need to cross the road. The measure, combined with other types of crossings, has reduced animal-vehicle collisions by half.

New York City suffered from fires that erupted in overcrowded, run-down apartments. Then the city sleuthed through residential records and found that landlords who foreclosed let their properties fall apart and ignored safety-code violations. Greater Toronto wants to expand upon New York City’s method by using transportation surveys, census data and computer data to build transit lines.

In a mountainous region of Lesotho, a man named Tsepo Kotelo visits 20 villages every week on his new motorcycle to provide health care to local villagers. The Elton John AIDS Foundation gifted the motorcycles to Kotelo and his colleagues, allowing them to increase the number of patients they visit by 600 percent. An organization called Riders for Health helps maintain the bikes, ensuring that remote villages will continue to receive medical care.

Ecological toilets that use natural composting to break down waste are simple to construct, waterless and are easy to fix. But as philanthropists are finding, getting these to those that need it most is harder than anticipated.

Civic leaders in the U.S. struggle to effectively help their distressed neighborhoods. East Lake, Atlanta, created a replicable model that mixes residents of differing socio-economic status, and focuses on education and health in the area.