D is for Dyson Sphere. Let your inner nerd out and just imagine it! The concept was created by Freeman Dyson and is so cool I wish we could make one. Basically you would build a sphere around a sun with planets. The sphere would help contain the energy from the sun. You would have limitless energy. Of course if you look at the image above you can see that the size of the sphere would be incredible. Larger than anything we could currently make. But, a girl can dream can't she?