London Subway Trains, London
With apologies to Beijing's subway system, the new cars for the London Tube should become the world's most impressive when they debut sometime in the 2020s. The next-generation trains designed by Paul Priestman will fill the Piccadilly, Bakerloo, Central and Waterloo & City lines with built-in Wi-Fi, evenly spaced double doors, air-cooling, LED lights that alert riders, and a style that eliminates the infamous gap everybody's been minding. Also, the new system will one day go driverless, and act as a contiguous tube rather than a series of cars, saving energy and promoting flexibility to meet route demands.