A wide river runs through a town. People need to get from one side to the other, so they build a bridge.

Every day, people walk across it. Cars and buses use it too. Some of these vehicles are very heavy. How does the bridge hold them?

A bridge is built to move weight through its strong parts and down to the ground. Some bridges have tall supports under them. Others use curved shapes or strong cables to help carry the load.

The people who design bridges are called engineers. They choose materials such as steel and concrete and work out how much weight the bridge must carry.

Bridges also need regular checks. Rain, wind, and years of use can damage them.

A girl crosses the bridge on her way to school. She may not think about the work behind it, but many people have helped make her journey safe.

The bridge is strong. People walk over it. Cars can go over some bridges too. People who build bridges must make sure they are safe. Bridges can look very different.