Thousands of years ago we had only one way to move—on foot. In today’s cities there are lots of ways to get around, including bikes, cars, mass transit (like buses, trains, subways, and ferries), escalators, and walkways. Engineers design solutions like these to transport people quickly, safely, and using the least amount of energy. But with so many people on the move, there are bound to be safety problems (like crashes), environmental impacts (like air pollution), and health impacts (like long commutes). Whatever the size and location of your future city, you’ll need to think creatively to keep people moving. Your challenge: Identify a problem of moving people in your future city and design a mode of transportation to solve this problem.