Book 3, Question 52
Why Do Bridges Have Arches?
An arch is a curved stack of stones or concrete. Weight from above squeezes the pieces together, instead of snapping them. That's why arches can be so strong!
From the book
Page from A Million Whys Book 3
More fun facts
- Arches let the Romans span wide rivers with fewer support piers.
- Roman stone arches were carefully built to spread out weight and stand up to the push of flowing water.
- Rebuilt in 142 B.C., the Pons Aemilius became Rome's first bridge made entirely of stone.
- The Pons Fabricius, with two wide arches each about 81 feet across, is the oldest bridge in Rome still in its original form.
- A Roman bridge at Merida, Spain, stretches 2,592 feet across the Guadiana River and still has 60 arches.
- Nature builds arches too. Arches National Park in Utah has more than 2,000 named stone arches.
Sources: National Geographic, National Park Service
Questions kids ask
What is the oldest bridge in Rome?
The Pons Fabricius is the oldest bridge in Rome that still stands in its original form.