Imagine yourself standing on one side of a raging, crocodile-infested river that you desperately want to get across, but swimming with crocodiles is out of the question, and walking around the river could take several days.
What should you do? Aha! Build a bridge!
From the earliest footbridges, built with a single felled tree trunk or flat stones, to modern structures made of spun steel cables, bridges have played key roles in our world. They have gotten us “to the other side,” protected us from enemies, and increased trade and long-distance travel. Bridges combine beauty with practicality. But why are some curved and others straight? Why are some made of stone, others of wood, and yet others of steel and aluminum? Read on to find out.