An interesting visual guide to fictional megastructures, like Larry Niven’s Ringworld, Arcologies, and Dyson Spheres:

Megastructures: The Visual Encyclopedia is part science book, part inspirational artbook. It contains everything from orbiting space habitats to solar system spanning stellar engineering projects. Each of the 40 structures in the encyclopedia includes a scientific explanation, followed by paintings and diagrams that bring the concept to life.