10. Light up your city at night

There’s much, of course. For example: Seoul has no sirens. Not a single one heard in 10 days. A city official says technology solves a lot of problems because they can track calls along with available police cars, fire trucks, and ambulances. Seoul is incredibly clean. No one seems to litter except an occasional foreigner. Even then, street workers come along and sweep it up. It has greenery everywhere, not to mention free wi-fi. And its buses are color-coded so you can spot which is yours from a distance.
Next, read about the Top 10 Secrets of Grand Central Terminal. Julia Vitullo-Martin is a senior fellow at the Regional Plan Association. Get in touch with her @JuliaManhattan.