A look at the design and creation of some of the biggest machines and buildings in the world. / How did bridges evolve in size from tiny bamboo walkways spanning streams to long suspension bridges connecting distant islands? How did buildings surge in stature from ground-hugging houses to cloud-busting skyscrapers? We reveal evolutionary engineering leaps that enabled different types of structures to explode from big to bigger to biggest. / (Source: National Geographic) Currently 8.5/10