Cities stand at the very center of each and every one of the biggest challenges the world now faces.
Despite major advances, the world's slum population will likely double to 2 billion by 2050.
A video follows Carol Ott, a mother of two who is documenting every blighted property she can find in Baltimore.
Carol Ott spends her days publicly shaming bad property owners, despite hate mail and death threats.
34 Roma people have been removed from their makeshift homes outside Spain's capital.
Add Vice President Joe Biden to a list that includes Ed Helms, Bradley Cooper, and Michael Jackson.
The city has about 16,000 empty buildings, and it's developed a unique program to rehab a small number of them.
Former Barcelona mayor Joan Clos warns that a lack of urban planning could turn our expanding cities into powder kegs.
Architects NLE are putting the finishing touches on a three-story, 2,300-square-foot floating school for 100 students in Lagos.
"We're creating a huge urban underclass of people who can’t function in the society."
An online forum invites insight from the people who work on the ground in the world’s biggest and most dysfunctional cities.
The walkable, bikable suburb of the "future" looks an awful lot like the smart growth ideas of today.
Quasi-legal buildings are popping up for rent all over the city, and officials are doing little to regulate these Dickensian dwellings.
Stilted homes over the water are being taken down by the government, leaving thousands homeless.
An upgrading effort in Kenya's slum leaves thousands homeless
An urban escalator opens in hilly Medellin slum
Governments are struggling to move into gang-dominated slums in the cities of Latin America
A sustainable development expert on how African cities should handle the continent's urbanization boom