Twenty-five years ago, the tragedy at the World of Primates building broke the city’s heart and raised a loaded question: What, exactly, do we owe the animals in our care?

Kathy Wylde’s winding path from community organizer to “lone defender of the billionaires.”

The rise and fall of Quayside, a futuristic city concept that Google’s Sidewalk Labs planned to build in neglected part of Toronto.

What kinds of space are we willing to live and work in now?

24 hours inside San Francisco’s homelessness crisis.

The story of a broken neighborhood.

A story of unhappiness and creative outlets.

"Last winter, when she was supposed to be designing a parking garage for a luxury shopping center in McLean, she built a city instead. She got the idea when she was surveying the lot where the parking garage was supposed to go. In her leather pumps and peacoat, she stood on the flat expanse and looked out; the land was a deep brown, lightly marbled with snow. She walked the perimeter, her hands in her pockets, her heels sinking into the dirt, her breath a white cloud in the air. She felt on the edge of something."

On the development of South Korea’s New Songdo and Cisco’s plans to build smart cities which will “offer cities as a service, bundling urban necessities – water, power, traffic, telephony – into a single, Internet-enabled utility, taking a little extra off the top of every resident’s bill.” The demand for such cities is enormous:

China doesn't need cool, green, smart cities. It needs cities, period -- 500 New Songdos at the very least. One hundred of those will each house a million or more transplanted peasants. In fact, while humanity has been building cities for 9,000 years, that was apparently just a warm-up for the next 40. As of now, we're officially an urban species. More than half of us -- 3.3 billion people -- live in a city. Our numbers are projected to nearly double by 2050, adding roughly a New Songdo a day; the United Nations predicts the vast majority will flood smaller cities in Africa and Asia.