Bridges are really cool structures that allow people to cross over a gap or an open space. Examples of times people use bridges are to cross a river or a lake. Bridges need to be built in a very special way: they can’t weigh too much or they’ll fall but they have to be sturdy enough to support people and lots of cars.

There are six types of bridges, but the most common types of bridges are beam bridges and suspension bridges. Beam bridges work by bending downwards as cars and people travel across. Engineers building beam bridges need to do their best to ensure that the bridge can hold a lot of weight without bending too far down and snapping in half.

A suspension bridge is the second most common type of bridge. There are lots of famous bridges that are suspension bridges, like the Golden Gate Bridge in California and the Brooklyn Bridge in New York. Suspension bridges have cables that distribute the weight of the actual bridge between two tall towers. This makes the bridge able to carry really heavy loads.

Bridges have been used by many ancient civilizations. A great example is the Inca Bridge. This is an example of a suspension bridge used by a civilization from thousands of years ago. This bridge had a wooden plank in the middle that made it easy for messengers to communicate up and down the mountain. However, if any attackers tried to use the bridge, the Incans would take away the plank. This made it almost impossible for attackers to cross the huge gap.