Big, Bigger, Biggest

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)