Although you might be too busy to notice it, the urban landscape is constantly changing.

If it were possible to speed up time, you'd notice an undulating motion as cities are built, remodeled, and destroyed. In real time, however, it's easy to overlook the fact that vast tracts of urban land sit idle for months or even years while waiting for its next makeover.

And anytime something sits idle, it's 100 percent wasted.

Instead of ignoring these vacant lots, plazas and alley ways, see how four communities transformed them into productive spaces and centers. Even if it's only temporary.

Up Next: Pop-Up Farm