According to Wikipedia, “The parable of the broken window was introduced by French economist Frédéric Bastiat in his 1850 essay “That Which Is Seen, and That Which Is Not Seen” to illustrate why destruction, and the money spent to recover from destruction, is not actually a net benefit to society.” 

The broken window fallacy describes the things seen and the things not seen. If you break a window, then you have to use your money to fix it. This is the thing that is seen. What would have happened if you didn’t break the window? You would have used your money to buy something else that could have helped you in some way. This is the thing that is not seen. there are so many other things that you could use that same amount of money for that you used on the window that you broke. 

this same example can be used for the building of a bridge. When you build a bridge, then is can do things for others like create jobs. But what would the money have been used or if the bridge wasn’t built? Then something else could have been built instead and possible have made other ways for people to get jobs. Once the bridge is built, then you won’t need those workers anymore. Will they get fired or will you have another project for them?