There are breakthroughs in material science everyday. The biggest break through happened recently by henry bessemer in the 1800's, called the bessemer process.

There are breakthroughs in material science everyday. The biggest break through happened recently by henry bessemer in the 1800's, called the bessemer process. Steel and concrete will not be replaced anytime soon, with steels infinite fatigue life combined with concrete creating a tensegrity structure. It is the perfect combination for large, cheap and long life structures. I don't see a need for new materials to build "cities of the future" I think glass, steel and concrete are sufficient. Breakthrough with 10-1000x reduction in specific density I'd keep an eye out for in the next decade are metal-air batteries. Pick up a book on material science, learn the laws of physics. Do the Math. Build the robot. Save the world.