Before the High Line, Alfred Speer proposed a moving elevated sidewalk to relieve street congestion and ferry pedestrians up and down Broadway.
In 1974, Philippe Petit crossed a 1,350-foot-high tightrope between the Twin Towers--without safety nets or harnesses--in the "artistic crime of the century."
Restaurant Row was protected by the vigilante Guardian Angels in the 1980's. Today, a proposal for kiosks seeks to revive the area's foot traffic.
Compared to commercial jets, helicopters have relatively few regulations about where they can fly and land in and around New York City.
A $1.5 million sponge park along Brooklyn's dirty Gowanus Canal is part of a city-wide effort to use "green infrastructure" to manage rainwater and pollution.
LA homeowners are planting gardens between their sidewalks and streets. These parkway gardens could be a solution to providing healthy options in a food desert.
The NYC subway employs a fleet of over 300 cars that collect fares, clear and vacuum the tracks, help construction and conduct general maintenance.
Before he designed Rockefeller Center, Raymond Hood imagined constructing grand bridges across the rivers, held up by skyscraper apartments--a city on a bridge.
A $15 million donation from Google's Eric Schmidt allowed construction on Governors Island to start. It's the latest in private funding of public spaces.
Before it was the site of recessions and protests, Wall Street was an early Dutch fortification. It almost wasn't built though, thanks to some unruly pigs.