2. BRIDGES
 Bridges can cross water. Some bridges over
water move to let boats through. Others
are high enough that boats can pass
beneath. Bridges also cross valleys,
ravines, railroad tracks, roads, and other
things that block the way.
 Bridges can be made of many materials.
Early bridges were made of wood or stone.
Many wooden bridges were covered to
protect them from snow and rain so they
would last longer.

3. Golden Gate Bridge
 the golden gate Bridge is one of the world’s
most famous bridges. It spans the San
Francisco Bay in California.

4. Wooden Bridge
 Early bridges were usually made of wood
or stone. This covered wooden bridge is on
Virginia’s shenandoah riVer.

5. Ponte Vecchio
 The Ponte Vecchio (Old Bridge) spans the
Arno River in Florence, Italy. Built in 1345,
the bridge was one of the few in Florence to
survive the heavy bombing of World War II.

6. Ironbridge
 Ironbridge, located in Telford, England,
was the first bridge made entirely of cast
iron. It was completed in 1779.

7. London’s Tower Bridge
 The Tower Bridge spans the Thames River in
London, England. It has a drawbridge that
raises up to allow boats to pass through.

8. Suspension Bridge
 Suspension bridges hang from two large
main cables rather that resting on
supports underneath. The Clifton Suspension
Bridge, shown here, is located in Bristol,
England.